Let’s Look at: Zach Duke

Benny Sieu-USA TODAY Sports

Today we look at the Brewers’ most dominant reliever to date, Zach Duke. Duke has stymied both right and left-handed hitters this year, but came to the team in a shroud of mediocrity.

When he joined the Brewers as a Non-Roster-Invitee in Spring Training, Duke owned a 4.57 career ERA, and fans were not incredibly encouraged when he made the team as a reliever. Though Duke was an All-Star in 2009, he finished the season with a league-leading 16 losses.

Excluding his shortened rookie year, 2009 was Duke’s best as a starter, when he posted a respectable 4.06 ERA. Many analysts have blamed Duke’s ordinary career on the Pirates, who continued to try to make a starter out of him, despite his frequent struggles.

That point appears validated now that Duke is a top-tier reliever, but Duke has also changed his delivery, which could be a big factor. There are many ways to demonstrate Duke’s dominance, one of the best being that in his worst month, Duke still posted an ERA of 1.93 with an opposing SLG % of .333.

As mentioned, Duke has also performed just as well against righties as with lefties. Prior to today’s game, righties had posted a .524 OPS, while lefties have an OPS of .510. Also prior to today’s day games, Duke ranked 7th among qualified relievers in ERA (1.11) and 9th in FIP (1.71).

If incumbent set-up man Will Smith should continue to struggle, it seems plausible that Ron Roenicke could try Duke out in the eighth inning to see if the former starter can perform in high stress situations.

There is already proof that Duke can be clutch, however. According to Baseball Reference’s “Late & Close” metric (Plate Appearances in the 7th inning or later with the batting team tied, ahead by one, or the tying run at least on deck), opponents are slugging just .156 against Duke.

Perhaps most beneficial to the Brewers is that Duke has had his break-out season on an immensely team-friendly $850,000 salary. This has lead to speculation that the Brewers will attempt to re-sign Duke to a multi-year deal, though at the peak of his game, his requested salary may be over-inflated.

While it remains to be seen if the Brewers will retain Duke after 2014, he is presently posting elite numbers out of the bullpen, and remains a top reliever for the season.