American League Starting Pitcher Repertoire Changes

Change in pitch mix often coincides with a change in performance. It’s one of the few statistical changes we could identify immediately. So let’s take a look at which American League starting pitchers have changed their pitch mix versus last year the most.

I looked at pitchers whose fastball usage changed by at least 12% (up or down) and breaking balls that differed by at least 9%. I used the Pitch Type metrics, not the PITCHf/x Pitch Type numbers.

AL SP Pitch Mix Changes
Name FB% 2017 FB% 2016 SL% 2017 SL% 2016 CT% 2017 CT% 2016 CH% 2017 CH% 2016
Danny Duffy 47.30% 59.30% 30.20% 23.50% 22.40% 17.10%
Derek Holland 49.30% 61.40% 18.40% 13.90% 12.00% 10.20%
Danny Salazar 57.20% 68.30% 5.20% 7.90% 31.90% 18.80%
Erasmo Ramirez 40.40% 64.20% 9.90% 15.50% 25.60% 24.10% 19.50%
Dylan Bundy 52.20% 61.50% 20.70% 15.90% 20.10%
Andrew Triggs 43.90% 55.60% 23.30% 19.90% 32.40% 22.70% 0.50% 1.80%

Danny Duffy broke out last year when he was able to sustain most of his bullpen velocity gain in a starting role. While his velocity has regressed back to his pre-2016 days, plus an additional decline, he has thrown his fastball far less frequently than ever before. Instead, he has increased the usage of his slider and changeup. Usually, that kind of change is going to improve a strikeout rate, assuming those secondary pitches are at least decent. Duffy’s SwStk% has only dropped marginally and still sits at the second highest mark of his career, but his strikeout rate has plummeted. That hasn’t been because of the change in pitch mix, but because his four-seamer’s whiffiness has waned considerably.

With the decline in velocity and the SIERA more than a run higher than his ERA, he’s an obvious sell candidate soon as he has his first good start after returning from the DL. Speaking of velocity, anyone else notice his game log where his velocity shot up to near 95.0 mph in his second to last start before hitting the DL, then dropping right back down to 93 the following game? He hasn’t been above 93.3 mph in any other game, so that one start sticks out like a sore thumb!

Derek Holland suckered many a fantasy owner into picking him up when he was sporting a super fortunate 2.37 ERA (4.74 SIERA) after his first 10 starts. But since, in his four June starts, he has allowed a whopping 22 runs in just 15.2 innings for a massive 12.64 ERA! That includes starts of six, seven, and eight runs allowed, with a one-runner in the middle just for $hits and giggles. He has reduced his fastball usage in favor of his slider, which used to be excellent, as well as his curve ball. The changes have certainly helped, at least from a whiff inducing perspective. His SwStk% is up and his strikeout rate is at its highest since 2013. It’s too bad he can’t throw strikes. And allowing 40% fly balls in a hitter friendly venue is not going to end well!

Danny Salazar could thank his increased changeup usage for the bump in strikeout rate to over 30%. Unfortunately his control has deserted him and now he sits on the DL with a shoulder issue. I wouldn’t be surprised if his elbow wasn’t quite right either given those control problems.

Sometimes the pitch classification systems get confused by cutters versus sliders, but both agree that Erasmo Ramirez has suddenly started throwing a cutter this year, coming at the expense of his fastball. It hasn’t resulted in much change in his performance, but that’s because his cutter ain’t so hot. Then again, his two-seamer, which has become his fastball of choice this year, has been horrid at generating swings and misses. And the cutter is certainly better, but still well below where we would want to see it. He does need to figure out what to do with that two-seamer though, as although it gets grounders, it sports a .365 wOBA against for his career. So far the cutter is better, but still no great shakes.

The classifications have no idea what to call Dylan Bundy’s repetoire, as they disagree about one of his cutter/curve/slider every during his various times in the Majors. Whether you call it a slider or cutter, he’s throwing that pitch much more this season at the expense of his fastball. And since his fastball has lost quite a bit of velocity, moving away from it makes sense. The cutter/slider has been pretty amazing this year, generating a SwStk% above 20% and a .210 wOBA against. He should probably just scrap his curve ball, as it doesn’t get whiffs or ground balls and he already has a weapon (the change-up) against opposite handed batters.

With potentially strong skills in the triumvirate of strikeout, walk, and ground ball rate, Andrew Triggs was a legitimate sleeper. Sadly, his underlying skills have collapsed and he hasn’t yet made good on that intriguing upside. Like Ramirez and Bundy, he has swapped out his fastball for more cutters (or sliders if you check PITCHf/x). Based on its strong SwStk%, this looks to be an excellent move, but his SwStk% has barely budged, and we know his strikeout rate has slid significantly. Both his curve and two-seamer are sporting marginal SwStk% declines, which must be offsetting the gains from the increased cutter usage. The real problem here is the killer of throwing fewer strikes, and generating fewer called and foul strikes. If he wasn’t already 28 with a fastball that has dipped under 90.0 mph, I would share my enthusiasm of his future. But my excitement is dampened by those factors.





Mike Podhorzer is the 2015 Fantasy Sports Writers Association Baseball Writer of the Year. He produces player projections using his own forecasting system and is the author of the eBook Projecting X 2.0: How to Forecast Baseball Player Performance, which teaches you how to project players yourself. His projections helped him win the inaugural 2013 Tout Wars mixed draft league. Follow Mike on Twitter @MikePodhorzer and contact him via email.

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Turgidmember
6 years ago

The Orioles said cutters sap fastball velocity. Bundy started throwing his cutter and lost velocity. Seemed like they were being dumb, but maybe the Orioles were right