I created an NCAA basketball tournament "office" pool for AG.com readers, which you can sign up for by clicking here or going to www.madness.nbcsports.com and entering in the following information:

Pool ID: 2884
Password: Mila

All is quiet on the Joe Mauer front since false reports from Mark Rosen and Dan Cole claiming that an extension had been agreed upon, but that hasn't stopped the Twins from handing out other long-term deals. Last week Nick Blackburn inked a four-year, $14 million contract with an $8 million team option for 2014 and over the weekend Denard Span agreed to a five-year, $16.5 million deal with a $9 million team option or $500,000 buyout for 2015.

For both Blackburn and Span the Twins basically pre-paid for their remaining team-controlled seasons while securing a team option for their first season of free agency, with the only real difference being that Blackburn has accumulated one more year of big-league service time than Span and thus would have been eligible to hit the open market one year sooner. In other words, only the addition of a 2014 option for Blackburn and a 2015 option for Span alter how long the Twins would have been able to keep them.

Blackburn's contract struck me as an unnecessary risk without much upside, as they already controlled him through 2014 anyway and his skill set makes decline more likely than a breakout during the life of the deal. Because of that, committing $14 million up front when the Twins could have just taken things year-to-year with him is a questionable tradeoff in exchange for a bit of cost certainty and an $8 million team option on a 32-year-old Blackburn for 2014.

Span is a different story even through the contracts are nearly identical, because he's currently a clearly more valuable player than Blackburn despite being two years younger and also projects as more likely to maintain his performance long term. Not only is Span at $16.5 million for 2010-2014 more likely to be a bargain than Blackburn at $14 million for 2010-2013, there's a much higher chance that the Twins will actually want to retain Span for $9 million in 2015 compared to Blackburn for $8 million in 2014.

Here are the contract breakdowns, with "MIN" standing for minimum-salaried, pre-arbitration seasons, "ARB" representing arbitration-eligible seasons, and "FA" equaling free agency (numbers in millions):

             MIN2    MIN3    ARB1    ARB2    ARB3    FA1
Blackburn            0.75    3.00    4.75    5.50    8.00 option
Span         0.75    1.00    3.00    4.75    6.50    9.00 option/0.50 buyout

All of which isn't to say that Span's contract is a no-brainer for the Twins, because as someone whose big-league career consists of just 238 games in less than two full seasons and has been dramatically superior to his underwhelming minor-league track record there's some risk there too. He's gone from hitting .287/.357/.358 in the minors to .305/.390/.422 in the majors, upping his walks by 25 percent and showing 60 percent more power with 10 percent fewer strikeouts to emerge as an ideal leadoff man.

However, he's better and younger than Blackburn with less likelihood of a decline and far more upside, making him a much more viable and impactful long-term building block. And even my once-prominent (and warranted) skepticism of Span being the real deal has all but vanished during the past two years, so while the risk of up-front money outweighed the reward of cost certainty and delayed free agency for Blackburn taking the same plunge with Span was a lot more worthwhile. Now, about this Mauer guy ...

Yesterday afternoon Paul Charchian subbed for Dan Barreiro on KFAN and had me on as a guest to talk about the Twins for 20 minutes or so. We mostly discussed Joe Nathan, but also touched on a few other topics, and the segment was very enjoyable. If you missed it live, you can listen to the interview on KFAN.com. Just click here and zoom forward two-thirds of the way through the clip, when I come on.

This morning at 8:00 a.m. I'll be calling in to KSTP-1500 to chat about Nathan's injury and the Twins with Doogie Wolfson, which is always a good time. You can listen online by clicking here, and hopefully they'll also make the clip available to download afterward.

And last but definitely not least tonight at around 9:10 p.m. I'll be appearing on Seth Stohs' podcast, which is an absolute must-listen for any Twins fan because in addition to talking to fellow bloggers like me he typically has one or two players on each show as well. You can listen online by clicking here and Seth always makes the show available for download afterward.

UPDATE: Seth tells me that I can pick a song for my intro on the podcast, which now strikes me as the most important decision of my life. My first thought was something by Otis Redding, just because he's awesome. My second thought was "Big Poppa" by Notorious B.I.G., but upon inspection it may not work because he doesn't get to the hook until after some swearing. My third thought was "Stand Up" by Steel Dragon, which plays when Nathan comes out of the bullpen. Suggestions? Funny, serious, whatever.

When closer Joe Nathan left Saturday's spring training debut with pain in his surgically repaired elbow the Twins hoped it was merely scar tissue breaking up, but after flying back to Minneapolis for an MRI exam he's been diagnosed with a torn ulnar collateral ligament. Nathan is expected to rest for a couple weeks in an effort to find out if can possibly pitch through the pain, but more likely than not he's headed for season-ending (and at age 35, perhaps career-threatening) Tommy John surgery.

There's no getting around the fact that losing Nathan would be a huge blow to the Twins. Since arriving in 2004 as part of the famed A.J. Pierzynski deal he's been arguably the best reliever in all of baseball, saving 246 games with a 1.87 ERA and 518 strikeouts in 418.2 innings spread over 412 appearances. During that six-season span Nathan's adjusted ERA+ of 236 is the best of any pitcher with 300 or more innings, and Mariano Rivera at 234 and Billy Wagner at 202 are the only others above 200.

Nathan is irreplaceable because no other reliever will be able to match how consistently fantastic he's been with yearly ERAs of 1.62, 2.70, 1.58, 1.88, 1.33, and 2.10. He is not, however, irreplaceable simply because of the role he filled. Closers are made, not born, and despite what you may hear from people looking to build the role up into some kind of mythical test of wills the primary characteristic needed for handling ninth-inning duties is being a good pitcher. Period.

Nathan has been a great closer, but before that he was a starter moved to the bullpen because of arm injuries and had just one season as a setup man. Eddie Guardado was also a failed starter who spent a decade as a middle reliever before getting a chance to close, and then saved 86 games in two years. Rick Aguilera is another former starter turned reliever, and was 27 years old before recording his first save. Being an established closer isn't a prerequisite for being a successful closer.

Losing a great pitcher like Nathan hurts because the Twins don't have an equally great pitcher to take his place, not because the role he filled is much too vast and important for a mere mortal. Nathan was a mere mortal before assuming the role, as were Guardado, Aguilera, and so many other top closers. Nathan has converted 90.7 percent of his chances with the Twins, which is amazing, but the MLB-wide success rate for all closers is 86.5 percent and all but the disasters are usually around 80 percent.

Nathan has had 45.2 save opportunities per year and by converting 90.7 percent of those chances he's averaged 41.0 saves. An "average" closer converting 86.5 percent would have 39.1 saves and a "poor" closer converting 80.0 percent would have 36.1 saves. Per season that equals 1.9 fewer saves at 86.5 percent and 4.9 fewer saves at 80.0 percent. And it's important to remember that not every blown save ends in a loss, so being without Nathan will likely cost 3-4 wins including his work in non-save spots.

Ron Gardenhire hasn't dropped any hints about the replacement closer because he's still holding out a slim hope that Nathan can pitch through the injury, but bullpen depth was one of the Twins' strengths coming into spring training and he has several decent options from which to choose. I'd likely go with a closer-by-committee approach based on matchups, at least initially, but my guess is that Gardenhire's preference is to find one man for the job even if it takes giving a few guys tries before settling on him.

Matt Guerrier has been setting up Nathan for the past six seasons, with a 3.31 ERA in 389 innings as a reliever, but his raw stuff isn't exactly overpowering and more importantly his valuable ability to make multi-inning appearances or rescue other pitchers from mid-inning jams would likely cease given how Gardenhire has used his closer. In terms of raw stuff Jon Rauch is much more similar to Guerrier than Nathan even if standing 6-foot-11 with neck tattoos makes him look like a closer.

With that said, Rauch has more closing experience than the rest of the fill-in candidates combined and even if that basically amounts to just 17 saves with the Nationals two seasons ago I'll be surprised if it doesn't play a big factor in Gardenhire's decision making. Rauch as a closer is obviously far from ideal, but he has a 3.59 ERA in 363.1 innings as a reliever, including a 3.60 mark last year, and was indeed right "around 80 percent" when given regular save chances in 2008.

Jose Mijares had a good rookie season with a 2.34 ERA in 62 innings and was often billed as a future closer while coming up through the minors thanks to raw stuff that sits a step above guys like Guerrier and Rauch, but Gardenhire seems unlikely to trust a second-year pitcher in the ninth inning right away. Mijares also allowed right-handers to hit .283 with a .791 OPS last year while completely shutting down fellow lefties, so for the short term at least he's probably best suited for a semi-specialist role anyway.

Once upon a time Jesse Crain was also thought of as a future closer and still has the mid-90s fastball for the job, but he's hardly been consistently reliable even as a setup man and spent six weeks of last year at Triple-A following a midseason demotion. Setting aside whether Crain could handle closing I'd be shocked if Gardenhire trusted him enough to give it a try, which is also why prospects like Anthony Slama and Robert Delaney aren't realistic options.

Francisco Liriano may be an intriguing closer candidate, but if he looks good this spring the Twins will want him in the rotation for 200 innings rather than the bullpen for 70 innings and if he isn't impressive in camp they surely won't be handing him late leads. Pat Neshek emerged as Nathan's top setup man in 2006-2008 with a 2.91 ERA and 142 strikeouts in 121 innings and might be the leading candidate to step into the job if not for the fact that he's coming back from a Tommy John surgery of his own.

Neshek's recovery is said to be going well and his spring training debut last week was promising, but he hasn't thrown a regular-season pitch since May of 2008. Tossing him right into the ninth-inning fire is highly unlikely and probably ill-advised. And while his vulnerability to left-handed batters was grossly exaggerated before the surgery he certainly benefited from being used in spots that weren't heavy on lefty sluggers. He'd benefit from that now more than ever, but it isn't doable for a one-inning closer.

Before the surgery Neshek would have been my choice to step in for Nathan and even after the surgery if healthy he'd be a good fit in a closer-by-committee situation with Mijares, but with his status up in the air and no need to rush him into anything it's a moot point. And of course Gardenhire is unlikely to use multiple, matchup-based closers anyway. At some point pining for Mijares, Neshek, or Mijares/Neshek could make sense, but for now Gardenhire may lean toward Rauch and I'd find it hard to disagree.

Whatever happens the bullpen's depth has the Twins remarkably well-positioned to handle losing their stud closer and any decision Gardenhire makes will likely result in less of a game-saving dropoff than most people seem to think. Nathan has been spectacular, but the role he's filled is so rigid and fawned over that the gap between truly "great" and merely something resembling "mediocre" in the ninth inning is typically overstated and often unpredictable, with last year providing a pair of prominent examples.

MLB's best save percentage belonged to Fernando Rodney, a 32-year-old career-long setup man with a 4.28 ERA who went 37-of-38 for Detroit. Philadelphia won 93 games and the NL pennant despite one of the worst closer seasons ever by Brad Lidge, who went 0-8 with a 7.21 ERA and MLB-high 11 blown saves. Nathan's injury drops the Twins' playoffs chances, which is difficult to stomach after a productive offseason had the team looking so strong, but they can definitely survive and even thrive without him.

And maybe the Twins will stumble upon their next great closer in the process.

My NBCSports.com/Hardball Talk colleague Craig Calcaterra reports live from the Twins' clubhouse in Fort Myers that Joe Nathan has a torn ulnar collateral ligament in his right elbow and will likely undergo season-ending Tommy John surgery. Before going under the knife he'll rest for 2-3 weeks to see if he could possibly pitch through the injury, but Ron Gardenhire called it a "significant" tear and Craig notes that "everyone's body language and mood is that they're pessimistic and surgery is going to happen."

Damn. Just ... damn.

UPDATE: I'll have much more tomorrow, but for now here's my quick take on the closer options.

There were two prominent bits of Twins news over the weekend, as Joe Nathan left Saturday's game with soreness in his surgically repaired right elbow and Nick Blackburn signed a four-year, $14 million contract with an option for 2014. I'm hesitant to comment much on Nathan's status until further details are known, but he flew from Fort Myers to Minneapolis yesterday to undergo an MRI exam and the hope is that the pain was from scar tissue breaking up following October 20 surgery to remove bone spurs.

As the 35-year-old closer put it: "We're going to get some pictures just for some peace of mind." Joe Christensen of the Minneapolis Star Tribune reports that doctors will compare his current MRI results to his pre-surgery exam and proceed from there, with a couple days of rest to deal with the scar tissue qualifying as the best-case scenario and going under the knife again to fix a separate injury looming as the worst-case scenario. And no reason to panic in the meantime.

While the Twins hold their breath waiting for word on Nathan's elbow, they signed Blackburn to a deal that could keep him in Minnesota through 2014. However, he was already under team control through 2013 via arbitration eligibility. Rather than being a true "extension" the contract pays him $750,000 this season, pre-pays $13.25 million for Blackburn's three arbitration-eligible years in 2011-2013, and then gives the Twins an $8 million option for his first season of free agency in 2014.

Cost certainty during the arbitration process is important for the Twins and the deal ensures Blackburn won't file for a big salary following a particularly strong season, but because they're paying for what he will do rather than what he has done the downside is that cutting bait is no longer a choice if injuries or poor performances strike. The ability to delay free agency for another season also has value, although there's certainly no guarantee that they'll want to pay $8 million for a 32-year-old Blackburn.

When he was coming up through the minor leagues I pegged Blackburn as little more than a potential fifth starter or long reliever, criticizing Baseball America for ranking him as the Twins' best prospect as a 26-year-old in 2008. Since then he's significantly outperformed my expectations, beginning his career with back-to-back solid and (nearly identical) seasons as a durable middle-of-the-rotation starter who led the team in innings both years:

YEAR     GS      W      L      ERA        IP     SO     BB     HR     OAVG
2008     33     11     11     4.05     193.1     96     39     23     .292
2009     33     11     11     4.03     205.2     98     41     25     .290

You'd be hard-pressed to find many starters who began their career with more similar seasons and it's easy to see why the Twins think Blackburn is a big part of their future. However, his minuscule strikeout rates and high opponents' batting averages put him at risk to age poorly and the underlying numbers in his performance are closer to a 4.50 ERA than a 4.00 ERA. Toss in the fact that they could've controlled him through age 31 with no upfront commitment and the deal has some risk without much upside.

Blackburn has been a solid, dependable mid-rotation starter and is now entering just his third season, so the tendency is to assume that he'll naturally either maintain his performance or get better. He may do exactly that, in which case locking him up through 2014 at a total cost of $22 million would look like a steal, but many people felt the same way about Joe Mays and Carlos Silva once upon a time before the often sobering reality of low-strikeout pitchers without heavy ground-ball tendencies set in.

I'm generally in favor of locking up young players to long-term contracts, but logically not every instance of doing so is by definition a smart decision even if a certain segment of the fan base will automatically default to that assumption. In this case cost certainty comes with the risk of Blackburn tripping on the fine line he's walked thus far and there isn't a ton of value in having the right to pay him $8 million as a 32-year-old, so I would've gone year-to-year with him and let things play out from there.

That the Twins feel differently certainly isn't surprising because they're likely focused much more on his 4.04 ERA through 66 career starts than what his lack of missed bats and modest number of ground balls say about his chances of keeping that up for another 125 starts. I've been wrong about Blackburn through two seasons and hopefully I'll also be wrong about his next four or five seasons, but to me this is an unnecessary commitment with less upside and more downside than perhaps meets the eye.

My annual series ranking and profiling the Twins' top 40 prospects concluded last week, so here's the complete list, along with links to each individual write-up and an overview of the whole system:

 1. Aaron Hicks, CF                21. Alex Burnett, RP
 2. Kyle Gibson, SP                22. Robert Delaney, RP
 3. Wilson Ramos, C                23. Luke Hughes, 3B
 4. Miguel Angel Sano, SS          24. Ben Tootle, RP
 5. Ben Revere, CF                 25. Deolis Guerra, SP
 6. Angel Morales, CF              26. Shooter Hunt, SP
 7. David Bromberg, SP             27. Trevor Plouffe, SS
 8. Danny Valencia, 3B             28. Michael McCardell, SP
 9. Matthew Bashore, SP            29. Reggie Williams, 2B
10. Billy Bullock, RP              30. Estarlin De Los Santos, SS
11. Rene Tosoni, RF                31. Derek McCallum, 2B
12. Chris Parmelee, RF             32. Jose Morales, C
13. Adrian Salcedo, SP             33. Chris Herrmann, LF
14. Joe Benson, CF                 34. Bobby Lanigan, SP
15. Jeff Manship, SP               35. Danny Rams, C
16. Tyler Robertson, SP            36. Josmil Pinto, C
17. Carlos Gutierrez, RP           37. Steven Tolleson, 2B
18. B.J. Hermsen, SP               38. Anderson Hidalgo, 3B
19. Anthony Slama, RP              39. Loek Van Mil, RP
20. Max Kepler, CF                 40. Joe Testa, RP

Most years at least a handful of significant prospects from my top-40 list exhaust their rookie eligibility or leave the organization via trade, but last season only Anthony Swarzak, Brian Duensing, and Jose Mijares graduated to the majors and only Kevin Mulvey was dealt away. That atypical lack of turnover combined with the addition of high-end talent like Kyle Gibson, Miguel Angel Sano, Matthew Bashore, Billy Bullock, and Max Kepler makes the 2010 list much stronger than the 2009 version. And different.

For the past few years the Twins' minor-league system was long on depth and short on star potential, but the opposite may now be true. While the system still lacks elite MLB-ready talent--Danny Valencia is the only top-10 guy who seems likely to play a big role in the majors this season--the Twins boast four of the top 75 or so prospects in all of baseball thanks to using their past two first-round picks on Aaron Hicks and Gibson, dropping a record bonus on Sano, and Wilson Ramos' continued progress.

On the other hand the second half of this year's top 40 seems weaker than previous versions, although certainly that's a tough thing to accurately gauge. Of course, if given the choice strong in top-end talent and weak in mid-level depth is clearly preferable to the opposite and the potential shift in organizational strategy is a positive one. Taking more chances and spending more money on high-upside prospects is absolutely the way to go for a team that may never out-spend the big boys for major-league talent.

As an organization the Twins have long thrived at churning out potential mid-rotation starters, but it now appears to be a relative weakness within the system and instead their minors are flush with outfielders (Hicks, Ben Revere, Angel Morales, Rene Tosoni, Chris Parmelee, Joe Benson, Kepler) and relievers (Bullock, Carlos Gutierrez, Anthony Slama, Alex Burnett, Rob Delaney). However, some things never change and they still haven't figured out how to develop middle infielders who can field and hit.

Sano was officially signed as a shortstop, but has about as much chance of reaching the majors at the position as I do and may not even stick in the infield once his 6-foot-3 frame fills out (sadly my 6-foot-2 frame has already filled out too much). And after that the best SS/2B prospects are Trevor Plouffe (27), Reggie Williams (29), Estarlin De Los Santos (30), and Derek McCallum (31). I've blogged about the Twins and their prospects since 2002, and young infielders have been a weakness the entire time.

Last year at this time I described the Twins' system as "right in the middle of the pack" amongst all 30 teams, but they're now safely in the upper half and probably in the 10-12 range. With that said, the main problem with making those team-to-team comparisons is that young non-prospects get totally ignored. In other words, prospects are technically only "prospects" until they play regularly in the big leagues, at which point they simply become "young major leaguers."

There aren't as many lists ranking those guys, but the future of a team is clearly about more than which youngsters retain prospect status by not using up their MLB-defined rookie eligibility. For instance, had Swarzak thrown just nine fewer innings last year he'd be eligible for this list, but his long-term potential doesn't change because he's absent from the top 40. With all that in mind, here's an organization-wide view of key Twins who're 29 years old or younger, including both prospects and non-prospects:

CATCHER:                   FIRST BASE/CORNER OF:      CENTER FIELD:
Joe Mauer, 27              Justin Morneau, 29         Denard Span, 26
Wilson Ramos, 22           Jason Kubel, 28            Aaron Hicks, 20
Jose Morales, 27           Delmon Young, 24           Ben Revere, 22
Danny Rams, 21             Rene Tosoni, 23            Angel Morales, 20
Josmil Pinto, 21           Chris Parmelee, 22         Joe Benson, 22
                           Chris Herrmann, 22         Max Kepler, 17
 
SECOND BASE:               SHORTSTOP:                 THIRD BASE:
Alexi Casilla, 26          J.J. Hardy, 27             Brendan Harris, 29
Matt Tolbert, 28           Miguel Angel Sano, 17      Danny Valencia, 25
Reggie Williams, 22        Trevor Plouffe, 24         Luke Hughes, 25
Derek McCallum, 22         E. De Los Santos, 23       Anderson Hidalgo, 21
 
RH STARTER:                LH STARTER:                RELIEVER:
Scott Baker, 28            Francisco Liriano, 26      Pat Neshek, 29
Kevin Slowey, 26           Glen Perkins, 27           Jose Mijares, 25
Nick Blackburn, 28         Brian Duensing, 27         Jesse Crain, 28
Anthony Swarzak, 24        Matthew Bashore, 22        Billy Bullock, 22
Kyle Gibson, 22            Tyler Robertson, 22        Carlos Gutierrez, 23
David Bromberg, 22                                    Anthony Slama, 26
Adrian Salcedo, 19                                    Alex Burnett, 22
Jeff Manship, 25                                      Robert Delaney, 25
B.J. Hermsen, 20                                      Ben Tootle, 22
Deolis Guerra, 21                                     Loek Van Mil, 25
Shooter Hunt, 23                                      Joe Testa, 24

Plenty of players aren't listed above, but that should provide an outline of the Twins' depth at each spot.