Is Guerrier closer material?

For two consecutive seasons, the Twins appeared hell-bent on getting Matt Guerrier's arm to explode in the socket. Guerrier, treated like an unlimited resource, belabored through a vicious drop in productivity in the second-half of 2007, which came in a year when he was used in 73 games for 88 innings. The following season his number was called a league-high 76 times. To make matters worse for himself, he was as inefficient as a corporate employee with a Twitter account. His bloated walk rate and nightly late fall thumpings seemed to reaffirm this notion. Because of this, many anticipated Guerrier to slink into a less demanding role in the pen in 2009 – this analyst included.

Unwilling to listen to what analysts had to say, Guerrier regained his status as an elite member of the Twins bullpen in 2009. Leading the league in appearances once again, he became more efficient, throwing more strikes and fewer pitches. His revival season which consisted of a 0.97 WHIP and a .212 opponent batting average has positioned Guerrier as one of the internal candidates for the vacant closer position. After Joe Nathan's announcement earlier this week, Guerrier said that he would "welcome the challenge" and would "love the opportunity" to close - key phrase I like to use when up for promotion as well. He's got solid credentials, but does he have upper management potential at Twins Bullpen Inc?

In many ways his spring has been a continuation of last season. The righty has thrown seven innings in six appearances, surrendering just one unearned run on six hits while striking out three and not issuing any walks. Combine this performance trend with the larger sampling of '09 and Guerrier is well-deserved of the promotion. He's worked in the high-leverage situations and has escaped unscathed in plenty of chances. After all, the results speak for themselves.

Nevertheless his 2009 performance review a cross-section of his body of work raises red flags, leading to questions regarding the probability of continuing this high level of success.

One of his biggest improvements between 2008 and 2009 was throwing from the stretch. When runners were on base in 2008, Guerrier was smashed more often than the writers of Hot Tub Time Machine. However the following year he became virtually unhittable under the same circumstances:

2009

2008

Bases Empty

.722

.750

.730

Runner On

.864

.677

(via Baseball-Reference.com)

This development coincided with his ability to keep the ball down in the zone in 2009 while working out of the stretch. After elevating the ball into the upper third of the strike zone 34% of the time in '08, Guerrier managed to stray up into that portion just 22% of the time in '09. Instead, he worked low in the zone to induce softer contact hence, the decline in the OPS allowed. Even with his adjustments, like most law of averages cases, the probability that his "Runners On" OPS remains that low is unlikely.

Furthermore, Guerrier's overall batted ball numbers merits a closer examination:

2009

2008

Lg. Avg

Career

GB

.246

.240

.218

FB

.085

.134

.123

LD

.628

.821

.741

Overall BABIP

.214

.306

.300

(via Baseball-Reference.com)

Across the board, no matter what method the ball was put into play, he posted averages below both the league and career marks. This serious syncline in these numbers does not correlate with any particular change in his approach. Usually when you witness batted ball averages shift this dramatically, it is associated with a new pitch or the increased usage of a pitch. Guerrier, by his own admission, hasn't altered his approach at all and his pitch data corroborates his story. He simply used his same four-pitch arsenal only allowing greater amounts of contact. While he's getting weaker contact, opponents are still doing so at a high rate and those numbers are ripe for regression.

Additionally, Guerrier's always been susceptible to allowing a good portion of fly balls to wander over the fence (11.1% career HR/FB). His control and batted ball numbers served him well by limiting a majority of those to the solo variety this past season. As presumably more runners reach base in 2010, some of those homers will score multiple runs. That does not translate well in the one- or two-run save situations.

Without question, based on his recent track record, Guerrier has earned the promotion. The results were exceptional in '09. Unfortunately, that does not always make you qualified for the job. Guerrier's skill set is better suited for middle management where he can continue to toe the company line: Throw strikes and hopefully good things happen.

Elsewhere in the TwinsCentric universe: