This will get very statsy very quick, please hang in here with me. I’ll start with the end first: Jake Diekman has become a solid relief option for the Phillies in 2013 and should be one of the few arms they should pencil in on the 2014 roster, despite a reduced strikeout rate.
Here’s the strikeout rate, click to enlarge:
Diekman’s bread and butter, and the calling card that got him to the Major Leagues, was his ability to strike batters out using his mid-90’s fastball out his his 6.5/8ths arm slot. He has sacrificed that this year in the name of control and the results have been favorable, click to enlarge:
Diekman has reduced the number of walks he issues per nine innings by nearly two. While he is still issuing a free pass more often than once every two innings pitched, Diekman has demonstrated more control at the Major League level in 2013 and has posted BB/9 IP numbers similar to what he had posted in the Minors.
Diekman has reduced his walks and has seen his strikeouts fall with it but this is a trade-off I would take. Diekman’s .356 BABIP indicates he has been a bit unlucky and has been rewarded with about a 53-point adjustment when comparing his ERA to his FIP, or Fielding Independent Pitching. His 3.44 FIP puts him in the sixtieth percentile of qualifying relievers, meaning he’s been an above average reliever in a small, 22.2 inning sample.
Diekman’s improvement has been one of the under-the-radar, quality performances on a Phillies team that lacks such things. If he can continue to improve his control, reduce walks, and slowly find more strikeouts, Diekman can be a very powerful bullpen weapon for the Phillies in 2014 and beyond.