Nathan's Replacement

The Twins were dealt a big blow on Tuesday when they received word all-star closer Joe Nathan will be out indefinitely with a torn ulnar collateral ligament and could eventually have to have Tommy John surgery if his condition doesn't improve. So this now begs the question of who can fill in as Nathan's replacement. The 3 candidates we'll take a look at are Jon Rauch, Matt Guerrier, and Jose Mijares.

RHP, Jon Rauch
Rauch is the one pitcher who has some closing experience, having racked up a career total 26 saves. After coming off of a fairly strong season with the Nationals and Diamondbacks in 2008, Rauch saw his strikeout rate drop from 8.29 K/9 to 6.30 K/9 and his walk rate jump [slightly] from 2.01 BB/9 to 2.96 BB/9. Another declining trend in Rauch's peripherals has been his batting average against, which has been on the rise since 2005:

2005: .221
2006: .232
2007: .233
2008: .255
2009: .262

Another thing work mentioning is that Rauch has always put up a higher FB% than GB%, which could be a bit problematic pitching in front of what appears to be an awful defensive outfield. When you look at Rauch's splits, 1 thing that immediately jumps out is the walk rates; against LH hitters, Rauch registered a 5.52 BB/9, but only a 0.92 BB/9 against RH hitters. Another interesting thing in his splits is that RH hitters registered a line drive percentage 7% higher than LH hitters, as well as a 13% higher FB%.

RHP, Matt Guerrier
Guerrier is an interesting candidate; hes not a swing-and-miss guy - 5.54 K/9 in 2009, career 6.01 K/9 -  but he does do a good job of pounding the strikezone, as evident to his 1.89 BB/9 in 2009 and career 2.81 BB/9. While the Minnesota outfield defense doesn't look to be all that good, the infield defense is quite the opposite, which matches up well with Guerrier's tendency to get more groundballs than flyballs.

Guerrier has some downsides, however. While the 2.36 ERA and 0.97 WHP looked very pretty, a closer look at some of his advanced stats might tell a different story. The opposing batting average was a shiny .212, but that was in large part due to a very fortunate .222 BABIP, so it seems reasonable to project both of those to rise next year. And despite the low ERA, more advanced ERA-scaled stats such as FIP, xFIP, and tERA were fairly modest on Guerrier last year  - 4.35, 4.31, and 4.40 respectively. Guerrier's splits weren't all that different other than a higher HR rate vs RH hitters and a higher GB rate vs LH hitters.

LHP, Jose Mijares
Miajres is coming off of a great first-full major league season in which he registered a stong 8.03 K/9 and .223 average against with a modest walk rate of 3.36 BB/9. His FIP and tERA were both very strong at 4.01 and 3.02 respectively. Unfortunately, that seems to be where the positives end for Mijares. His FB% last season was just over 50%, which once again could be problematic with the a Twins outfield of that features Jason Kubel, Michael Cuddyer, and Delmon Young as corner outfielders. Mijares' splits were pretty telling as well:

vs LH: 30.2 IP, 3.10 K/BB, 0.88 HR/9, 0.85 WHIP, 3.33 FIP, 3.88 xFIP
vs RH: 31.0 IP, 1.85 K/BB, 1.16 HR/9, 1.52 WHIP, 4.68 FIP, 4.98 xFIP

While his batting average against vs LH was certainly aided by a .190 BABIP, I think its easy to say Mijares is a pitcher one would prefer to primarily pitch vs LH hitters.

 

Overall, its actually a bit difficult to pick who is best suited for the role. Mijares appears to have the best swing-and-miss stuff but he struggled against RH hitters and put the ball in the air very often. Rauch seems like an okay choice but the walk rate against the lefties last year was pretty discouraging and he appears to be becoming more 'hittable' every year. This leaves us with Matt Guerrier - who yes, did have some good fortune with his incredibly low BABIP, but does a few things you want from your closer: he throws strikes, he can handle both LH and RH hitters, and he keeps the ball on the ground, which, for Minnesota, is critical.