2015 Phillies Report Card: Jake Diekman

When I evaluated Jake Diekman‘s season last year, I gave him an A- on the strength of unmistakable strikeout prowess. In 2014, Diekman struck out 100 batters in 71 innings, and finished the season seventh in the majors in strikeouts among qualified relief pitchers. He made a lot of appearances, ninth in the National League in that category. Manager Ryne Sandberg showed no mercy on the lefty, and also exposed Diekman by having him face too many righties. Though his strikeout numbers were elite, he had a 1.42 WHIP and a 104 ERA-, both of which were bad enough to place Diekman in the bottom quartile of relievers. In my 2014 report card, I argued that if Sandberg protected Diekman a little bit more in 2015 and didn’t have him face so many righties, it would help Diekman take the next step. 

Welp. In 2015, Diekman had a 1.75 WHIP with the Phillies in 36.2 innings. Even with a 0.92 WHIP in 21.1 innings as a Ranger after going to Texas in the Cole Hamels trade, Diekman’s 1.44 WHIP at the end of the season was the 14th-highest among qualified relievers. That’s a poor season, but it still seems fascinating to me considering Diekman’s great finish with the Rangers. After two full seasons in the big leagues and four years overall, Diekman has a career 1.44 WHIP. Nevertheless, I still believe in his stuff and his ability to become one of the game’s better relievers. In a two-month sample in the heat of a Texas pennant race, Jake Diekman showed how good he can be, and how impactful coaching and usage can be for relief pitchers.

Statistically, 21.1 innings in two months is meaningless in the context of Diekman’s 195 career innings. As with any type of ballplayer, relievers have ups and downs throughout seasons or across multiple seasons. But the dramatic difference in Diekman’s performances in Philadelphia and Arlington is undeniable, and is a reminder that, as brooksbaseball.net says, Diekman has electric stuff:

His sinker generates an extremely high number of swings & misses compared to other pitchers’ sinkers, is thrown at a speed that’s borderline unfair and has slight armside run. His slider generates a high number of swings & misses compared to other pitchers’ sliders, results in many more groundballs compared to other pitchers’ sliders and is much harder than usual. His change is thrown extremely hard, generates an extremely high number of swings & misses compared to other pitchers’ changeups, is a real worm killer that generates an extreme number of groundballs compared to other pitchers’ changeups, has an obvious armside fade and has some natural sink to it.

With the Phillies in 2015, Diekman’s performance was terrible. Then, as a Ranger, he somehow became a deadly weapon.

Jake Diekman Phillies Rangers
G 41 26
IP 36.2 21.2
TBF 175 85
ERA 5.15 2.08
ERA- 131 49
FIP- 92 86
FIP 3.65 3.60
WHIP 1.75 0.92
LOB% 69.6% 87.9%
AVG 0.268 0.169
BABIP 0.381 0.200
K% 28.0% 23.5%
BB% 13.7% 8.2%
K-BB% 14.3% 15.3%

So what happened? Well, Diekman cut his walk rate almost in half and saw his strand rate spike. His ERA- and BABIP fell off a cliff. But how, exactly, did Diekman produce such dramatically different results? Was it the change of scenery, leaving baseball’s worst team for a clubhouse jockeying for a postseason berth? After all, Diekman is from Nebraska. Maybe he just really didn’t like playing in Philadelphia and felt more comfortable closer to home. Maybe it was the Mike Maddux Magic? The Rangers pitching coach, perhaps, breathed his Maddux dust onto Diekman and changed him overnight. Maybe some or all of that helped.

But beyond the Land of Narrative Speculation, the Phillies saw a flaw with a player they scouted, drafted, and developed, and they fixed him. Diekman was sent down to the minors in June for two weeks, and was advised to adjust his arm slot to create more movement on his pitches. As much as Ryne Sandberg deserves criticism for overusing Diekman and his pitching staff as a whole, the Phillies deserve credit for knowing their players. But the Rangers saw something too, because after going to Texas, Diekman threw more sinkers and fewer sliders. He lost some strikeouts along the way, but generated more ground balls.

In 2015, Jake Diekman threw his fastball with an average velocity of 96.5 miles per hour (the same as Ken Giles). Diekman has nasty pitches, and is not as bad as his performance with the Phillies indicates. He was a painful but necessary addition to the Cole Hamels trade, and I believe Diekman can translate his arsenal of pitches into an elite season in 2016. As for 2015, the results are obviously mixed. There’s no denying his poor performance with the Phillies, just as it’s impossible to ignore his dramatic improvement with the Rangers. I’m grading Diekman on his performance, but also on his ability and potential. Call me a sucker, but I’m not ready to give up on Jake Diekman yet.

Grade: C-

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  1. Carmine

    October 16, 2015 11:29 AM

    Good piece. I hope we can dispense withe canard that the manager isn’t important. The handling of the pitching staff is crucial, and, with Diekman and DeFratus, Sandberg gave us a clinic on how not to do it.

  2. Mets_Fan

    October 16, 2015 04:16 PM

    The jury has to be out on Diekman as far as I’m concerned. His ability to miss bats is undeniably an asset, especially against lefties. That said, I don’t think his better numbers in Arlington justify calling him a “deadly weapon.”

    2015 is not, in my opinion, indicative of too much of anything. With the Phillies, his K% of 28% was even higher than 2014, but his walk rate also increased by a marginally higher proportional figure. But his BABIP was also very high – possibly because his GB% spiked by 13% (and increased even further in Arlington, as you correctly pointed out) – though I was surprised to see his BABIP increased in spite of a pretty significant reduction in LD% (from 26.3% in 2014 to 17.2% in PHI in 2015). His 3.65 FIP and 3.53 SIERRA with the Phillies indicate to me that he really wasn’t doing anything all too poorly, minus especially poor control (13.7% BB).

    In Arlington, what exactly changed? His K% dropped precipitously (in a kind of scary way – maybe as a result of a 10%+ increase in O-contact between his days in Philly and Texas and a pretty big drop in SwStr%), though his walks did as well. Did his profile as a pitcher completely change? No, not in my opinion. His FB% remained largely the same between Arlington and Philadelphia, though his BABIP fell through the floor, which helps explain why his FIP for both ball clubs was basically identical. He was a beneficiary of some good luck with one club and bad luck with the other. The results are so murky at this point, it’s hard to tell what this guy really is.

    The most perplexing news to me is his performance versus lefties this year…a .326 wOBA isn’t terrible, but it’s surprising given a .257 wOBA against lefties last year.

    I haven’t made much of a case for anything here, except that this is a really confusing case study and I think it’s almost impossible to predict future performance. Nice article though

  3. Romus

    October 16, 2015 05:56 PM

    Perplexing splits…..OBP vs LHB was better then RHB……367 vs .311—and OPS .729 vs .660
    And for a guy coming from the side, it is more hard to figure.

    • Adam Dembowitz

      October 16, 2015 06:11 PM

      I looked at his 2014 splits relative to his 2015 splits and just laughed out loud. I honestly have no idea. I thought it would be silly to try to unpack 58 innings of splits so I just let it go. But I did mean to address it at least on the surface and just forgot. Thanks Romus.

  4. ASK

    October 18, 2015 10:25 AM

    Diekman had a flare up with his medical condition (ulcerative colitis) that caused a huge weight loss prior to Spring Training. New medication seems to have the situation under better control, but it is quite possible that his improved performance throughout the season was tied to his improving health from April to October.

    • Adam Dembowitz

      October 19, 2015 11:52 AM

      I tried to fold the UC stuff into the article but it was feeling forced. I did read that he gets a treatment every 8 weeks and that he got one right around the trade deadline.

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