Peterson makes difference for Brewers

The Brewers likely had enough offense to be a playoff contender last season, ranking third in the NL in runs and OPS. But on the mound, they flat-out stunk. Their starting rotation had an ERA of 5.37 that was the worst in the NL and tied for worst in the majors. They also allowed the most homers and most walks in the National League.

In the offseason, they acquired both Randy Wolf and Doug Davis to bolster their pitching staff. But perhaps the most important transaction was the hiring of pitching coach Rick Peterson. Peterson is noted for his work with the Oakland Athletics in the late ‘90s and early ‘00s. Under his tutelage, the A’s staff finished in the top three in ERA from 1999-2003, including the AL’s best marks in 2002 and 2003.

With the Brewers, Peterson has stressed pitching to the bottom of the strike zone because "the average batting average… on every ball put into the play at the bottom of the strike zone is about .210 or .220."

The Brewers actually did this well last season, with 50% of their total pitches thrown in the bottom third of the zone according to Inside Edge, the 2nd-highest percentage in the NL. Their batting average allowed of .213 on those pitches down in the zone was also in-line with Peterson’s expectations.

Highest Pct of Pitches in Lower Third of Zone
National League, 2009 Season

Cardinals 53.3
Brewers 50.1
Braves 50.0

However, despite keeping the ball low in the zone, they were not able to generate a lot of groundballs. Only 44% of balls in play allowed were grounders according to Inside Edge, the 3rd-lowest percentage in the NL. That was likely one of the key reasons for their awful ERA, as they allowed a lot of line drive and flyballs, which resulted in a high number of extra-base hits and homers.

So how has the pitching staff performed this season, based on Peterson’s new philosophy of pitching down in the zone?

Through Saturday, the Brewers had kept 51% of their pitches in the lower third of the zone and allowed a batting average of .197 on those pitches – just what Dr. Peterson ordered! However, their groundball percentage was just 38.9% - not exactly the number you’d want to keep your ERA under five.

Randy Wolf – Sunday’s starter vs. the Cardinals – will need to improve on his first start performance if he’s going to avoid Peterson’s doghouse. Only 44% of his pitches were located down in the zone and he allowed a batting average of .250 on those pitches. His groundball percentage of 43% was also mediocre, and just 7 of his 20 outs were groundouts.

On the other side of the plate, the Cardinals hitters this season have not been impressive against pitches down in the zone, with a .182 batting average that is below the league average of .194. But – and Wolf will need to keep this in mind – 4 of their 9 homers hit this season have come on pitches in the lower third of the zone.

This should be an interesting trend to watch Sunday night and for the rest of the Brewers’ season. Can the Brew Crew pitchers continue to pound the lower part of the strike zone, and can they consistently generate enough groundballs to keep the runs off the scoreboard?

You can watch the Cardinals play the Brewers at 8 ET Sunday on ESPN.