Not enough good things have been said about Matt Guerrier’s 2009 season. After tailing off sharply in the second-half of the previous two year, the righty provided sustained dominance and gave the Twins a reliable bridge from starter-to-closer for the entire schedule. What was has been the difference for the six-year veteran?
In 2007, Guerrier roared through opponents from April until the end of July. In 60.1 innings of work, he possessed a solid 1.79 ERA and a .522 opponent OPS. By inciting a hefty amount of groundballs (47.6 percent), he was able to keep his batting average against at a tidy .188. Then the workload he amassed in the first four month began to show in August and September. Between the two months, he had worked another 27.2 innings but surrendered six home runs while allowing line drives on 20 percent of balls in play leading to a swollen .477 slugging percentage. The Twins had limited his role to sixth/seventh innings in the first half of the year, leading to a leverage index of 0.93 but increased his responsibilities in August where he finished the year working some of the most substantial innings with a 1.24 leverage index. Even with the digression in the season’s final two months, Guerrier’s overall numbers still looked good.
In the first several month of the following season, Guerrier retained his late season duties and was tapped to handle the difficult challenges. From April through June, Guerrier worked 44 innings and limited opponents to a decent .249 average while working in his highest leverage situations of his career (1.31). During this span, however, his walk rate had grown to 4.28 BB/9. His control was slowly eluding him as the season progressed. This control problem eventually manifested into being stuck behind in the count and forced to come in on hitters. In August and September, Guerrier threw a first-pitch strike on just 53.4 percent of his batters faced (his career average being 61.6 percent). Positioning himself in situations that often necessitated a fat fastball, opponents went 10-for-19 (.526) with five home runs after he fell behind in the count.
This output placed the Twins in a precarious position in the 2009 offseason. Guerrier was arbitration eligible and, if you subtract the month of September from 2007 and 2008, opponents had hit just.237/.299/.367 with 104/45 K/BB ratio in 586 plate appearances, which would make him a fairly solid candidate for a multi-year deal. Then again, in those two months of September, hitters had pasted him to the tune of .305/.394/.547 with a 23/13 K/BB in 109 plate appearances. In addition to that the workload combined with his age creeping into his 30s was enough to make one wonder if his arm was starting to experience some fatigue which might lead to some decline in the very near future. With question marks littering the bullpen, the organization sagely decided to sign him to a one-year deal, most or less to feel him out.
Instead of regressing, Guerrier responded big time. In 76.1 innings, he held opponents to a .212 batting average and lowered his walk rate from 4.4 to 1.9. Rather than nibbling with his heater as he had done so in the previous year, he sprayed the strike zone with his fastball – raising his in-zone presence from 48.5 percent to 57.4 percent. Opponents made a decent amount of contact (81.7 percent) but he kept the ball down in the zone better than he had the past two seasons which led to fewer hard hit balls and the 15th lowest batting average allowed in the AL (.212) among relievers – courtesy of a 60 percent groundball rate derived from his non-fastball offerings.
There is ample reason to celebrate his contributions in 2009, but is there evidence enough to think he will continue at this pace?
Judging from his 2-run difference between his FIP (4.35) and his actual ERA (2.36), Guerrier is a prime candidate to drop-off. Revisiting his batted ball numbers, we find that Guerrier’s .212 batting average allowed was heavily influenced by a freak-of-nature low batting average on balls in play. His .222 BABIP was the fourth lowest among AL relievers. This is not a trend that typically continues for a pitcher with average-to-above-average stuff; eventually the groundballs find seams and the fly balls find vacant land or carry over the fence. Needless to say Guerrier’s a much needed component of the bullpen, particularly because the return of Pat Neshek remains an unknown until spring. While he may be deserving of a multi-year deal based upon the majority of his performance, signing him to anything more than another season would be gratuitous.