Joe Nathan, one of the most reliable closers in the game (though there really is no such thing as a reliable reliever), has a tear in his UCL and is going to rest for two weeks before deciding whether to undergo surgery or not. Given the history of pitchers trying to rest and rehab, the odds are not on his favor. Tommy John surgery will very likely be in his future.

So this of course means without Nathan, the Twins bullpen roles are now up in the air. Instead of seeing Joe Nathan go in your auction in the $20's, you will see several pitchers go for more than they had in the past on the speculative chance they might get save opportunities. Let's consider the Twins options.

Jon Rauch is the favorite to take the job at this time. He has some closing experience under his belt and also has pitched in at least 74 games in each of the past four years. However, the cost of his 85 and 88 game seasons in 2006 and 2007 have taken their toll. His K/9 was the lowest of any full MLB season in his career at 6.3 0- not typically a closer-worthy mark. In addition, his BB/9 last season of 2.9 was solid; but it was a decline from his two previous seasons. Furthermore his home runs on fly balls stood 6.3|PERCENT| compared to his career average of 8.2|PERCENT| and his over 11|PERCENT| mark in 2008. He is a fly-ball pitcher, so I would expect some regression in this area. Before I get too depressing, there is some cause for optimism– over his very small sample size in Minnesota (15.2 IP) he did manage 14 strikeouts. So it is possible that moving from a non-contender to a contender reignited something within him, but I hate to come to any strong conclusions over such a sample.

Looking at his splits we have a pitcher who has typically been more effective against righties than lefties. This can be seen in his wide BB/9 splits (1.9 vs. righties and 4.1 BB/9 vs. lefties for his career). While the control issues remained static in 2009, he actually produced a higher K/9 against lefties than he did against righties and was perhaps the result of the development of a cut fastball. His K/9 against righties stood at sub 6.Given his history and no significant change in velocity or pitch selection, I suspect he can bounce back against righties in 2010.

In summation, we have a pitcher whose peek we have most likely already seen, but also a pitcher with enough skills and talent to repeat a sub 4.00 ERA. Just keep in the back of your mind his workload history and his command issues with lefties. The former could push him towards further decline and the latter could get him moved back into a setup/specialist type of role.  In AL only formats I would not be chasing him if the bidding gets into the mid to upper teens.

If you look back on Jesse Crain's career and pedigree, the closer job was supposed to have been his already.  Injuries have robbed him of this chance, but with Nathan gone there is opportunity. While he has reestablished himself as a fairly consistent 7+ K/9 pitcher, his once excellent control looks like a thing of the past. His BB/9 has declined for each of the past four seasons to an unacceptable 4.7 BB/9 last season. Crain looks like a strict right-handed specialist after posting an 8.4 BB/9 against lefties last season. He also has a career 4.7 BB/9 and a 5.8 K/9 for his against them. Interestingly he has posted an 8+ and 9+ K/9 against lefties each of the past two seasons, but his overall effectiveness against them has not improved. Like Rauch, Crain appears to be another pitcher who is already past his peek.

Matt Guerrier is another candidate to slide into the closer's role. In a continuing theme, Guerrier has been more effective against righties than lefties with a career 2.7 K/BB ratio against righties and a 1.6 K/BB against lefties. His K/9 against lefties has not been above 6.0 since 2005 and his BB/9 has fluctuated up and down a point or more on a yearly basis. Overall, his control was excellent last season at a 1.9 BB/9 and his 4.4 BB/9 from 2008 sticks out as an outlier when compared to career. Of concern, though was the decline of his overall K/9 from a 7.0 to a 5.5 from 2008 to 2009. This may be related to the strain of having pitched in an increasing number of games each of the past three seasons. Also, his 2.36 ERA from last year is sure to rise at least a point after producing an 86|PERCENT| left on base percentage and .222 BABIP over that same time period. For a third pitcher in a row we are once again seeing someone who is post-peek and is someone who could hang onto the closer's job if the opportunity occurred, but not someone who is a long-term solution.

Pat Neshek is the reliever on the Twins to most closely watch in spring training. From 2007 to 2008 he was a dominant setup man, but then ended up requiring Tommy John surgery which cost him all of 2009. He is now almost 16 months removed from the surgery and is once again pitching in spring training games. As with all pitchers coming back from Tommy John surgery, how well recovered he is can be assessed by noting his BB/9 and is what you need to watch this spring and into the early season. Neshek's control has been a strong part of his game throughout his career – 2.5 BB/9 in the minors and 2.8 in the majors – so use that as your baseline. Just also keep in mind that he is yet another Twin who has been more effective against righties than lefties – not surprising considering he is a sub-mariner. In his one full season of MLB duty, he produced an 11.0 K/9 and 2.9 BB/9 against righties, but just a 7.0 K/9 and 4.3 BB/9 against lefties. While it is possible he could be the Twins best option to close, it would once again be appropriate for them to use a lefty specialist in high leverage situations instead.

Jose Mijares is the Twins' one left handed reliever and as such will be utilized more in a setup/specialist role. Given the limitations of the others in the pen, he could also easily find end up in some crucial ninth inning situations. I would use a base of two or three saves as my starting point with him topping out in the high single digits when valuing him. In his rookie season he produced an 8.0 K/9 and 3.4 BB/9 while being used in less than inning per appearance, as expected of a situational lefty. His splits speak to his role with a 9.1 K/9 and 2.9 BB/98 against lefties , but with a still respectable 7.0 K/9 and 3.8 BB/9 against righties. Just be wary there is likely to be a correction upwards in his ERA and WHIP after producing a .266 BABIP and 89|PERCENT| left on base rat. It would not be surprising to see his ERA rise to the high 3's, if not the 4's. Adding to that fire – he is an extreme fly-ball pitcher (50|PERCENT| of the time) and only allowed 8.1|PERCENT| of his fly balls to turn into home runs, so that could correct upwards easily too.

Clay Condrey is the last MLB experienced option to discuss, but can be summed up quickly. He is a pitch to contact pitcher who posted a  .261 BABIP in 2009. He is also a clear right-handed specialist with splits of a  4.30 K/9 and 3.8 BB/9 vs. lefties compared to 6+ K/9 and 2.5 vs. righties. It is most likely he is intended to be used in long relief and for mop –up work.

So Nathan's injury leaves the Twins in a closer by committee situation. Key pitchers like Rauch and perhaps Neshek, if healthy, may be handed the reigns at different points in the season, but it strikes me that if the Twins are in contention, that they have shown in the past the willingness to trade for high profile relievers. To me it is more a question of when, not if, they will shop for another reliever. That adds even more risk when considering the Twins closing options this spring and ought to temper your bids accordingly too.