Sure, you can wait and see how rest and rehab help Joe Nathan recover from what has been termed as a “significant” tear in his UCL. Except doing that would be like ignoring the hurricane warnings while everyone else is buying plywood and generators. Dally at your own risk.
If Nathan does opt for the surgery, the Twins will have plenty of candidates vying for the closer role. Of the in-house relievers, Jon Rauch has the most experience as a saves guy, but in this case that’s not saying much. He briefly closed in Washington when Chad Cordero went down with an injury (17 saves in 22 chances for the Nationals in 2008) before he was traded to the Diamondbacks. During his time in the closer role in Washington he threw 48 innings, allowed just seven walks and 44 strikeouts while limiting opponents to a .232 batting average. In his career, he’s picked up a grand total of 26 saves. (Nathan saved his 26th game in mid July last year.)
Rauch is a guy you probably considered in AL-only leagues or deeper mixed leagues if you already drafted. He has shown the ability to strikeout roughly 8 K/9 and has solid control. His only drawback as a closer is the fact he’s an extreme fly ball pitcher. For his career he owns a 0.50 GB/FB ratio, but somehow he’s been able to dodge the long ball. Last year, he surrendered just six home runs in 70 innings of work. Not too shabby considering he doesn't use his infield all that much. The Diamondbacks dealt him to the Twins, which marked the second consecutive season Rauch changed uniforms in the middle of the year. That's because he's a quality arm to have in the bullpen.
Don't ignore his warning signs. His command is slipping ever so slightly and his strikeout numbers were off about 2 K/9 from 2008. Although he did throw more strikeouts after he moved to Minnesota (14 whiffs in 15 innings of work) this is a trend that bears watching. PECOTA thinks he can hold any further decline at bay for one more season at least with rates of 7.0 K/9 and 2.9 BB/9.
After joining the Twins, they threw him into the fire, which isn't anything new for Rauch. His Leverage was 1.32 and he finished with a 0.574 WXRL.
Matt Guerrier was an outstanding set-up man for Nathan last summer, leading the AL with 33 Holds. He doesn’t bring the heat (his fastball rests around 91 mph) but he makes up for his lack of strikeouts by featuring pin-point control. Last year, he struck out 5.5 batters per 9 while walking a career best 1.9 per 9. It also helped that Guerrier had an extremely low BABIP of .214. Add it all up, and you have an outstanding season. The question is, can he repeat?
The low BABIP obviously suggests he’s in line for a correction. And Guerrier has struggled before. As recently as 2008, he owned a 4.4 BB/9 and a .300 BABIP that led to his WHIP blowing up to 1.585 in what was a late season fade. The Twins worried about his durability down the stretch last year, but he experienced no such troubles. It’s too much to ask him to repeat last year’s 0.969 WHIP, but he’s much better than he showed in 2008. PECOTA is coming close to splitting the difference falling on the pessimistic side, calling for a 4.21 ERA and 1.36 WHIP. With a career HR/FB of 8.6%, he’s done well keeping the ball in the yard, but in the past he’s been prone to stretches of where he’s become hittable. He's more of a ground ball pitcher than any of the Twins closer candidates, so home runs shouldn't be much of an issue. He also benefitted from a strand rate of roughly 86% last year, compared to his career strand rate of 79%, which again suggests a correction is coming.
It should be noted that last year Guerrier handled the pressure of the late inning situations quite well. He was second to Nathan among Twin relievers with a Leverage score of 1.44 and a 3.478 WXRL.
Then there’s 25 year old Jose Mijares. Mijares sparkled last year with a 2.34 ERA and 1.184 WHIP. He doesn’t have the same outstanding control as his bullpen mates, but a 3.4 BB/9 isn’t too shabby. Mijares has less of a track record of the other two and really battled control issues in the lower minors. However, since 2008, he’s done a much better job at finding the strike zone.
What Mijares has is the confidence of his manager. Last summer, he owned a Leverage of 1.34, ranking him third on the Twins behind Nathan and Guerrier. His 3.425 WXRL was also third best in the Minnesota bullpen. That confidence was well deserved. In 90 high leverage plate appearances, Mijares limited the opposition to a line of .169/.205/.277 with 20 strikeouts.
The lefty Mijares still needs to learn how to put away right handed bats. Last year, hitters posted a line of .283/.358/.433 from the right side while shutting down leftys to a tune of .155/.228/.252. He's not the best candidate for the ninth inning until he figures this out.
The loss of Nathan certainly hurts, but all three closer candidates have the ability to deliver quality innings late in the game for the Twins. Ranking the relievers, you have to place Rauch at the top of the list. Move him up your draft sheets accordingly. Guerrier’s value moves up slightly as he would appear to continue to be an ideal set-up man while sliding in as the fallback guy for the saves. The youngster Mijares is the long-shot of the three to close, but he will get a chance at some point. Perhaps in 2011.