pERA Leaderboard: Starters

This past year, I created an ERA estimator which utilizes each pitch’s groundball and swinging strike rate and combines them for an overall pitcher ERA estimator (pERA). It’s time for a 2017 update. Today, I will go over some of the starters (min 5 starts) which stand out near the list’s top (full list).

Dallas Keuchel (#1, 2.14 pERA): Even though I expected Keuchel to be somewhere near the top of the list, I didn’t expect him to have the top spot. Two changes to his pitch repertoire have reversed his fortunes.

First, his elite sinker is getting 81% groundballs after generating 65% in 2016. The pitch is near his 2014 (77%) and 2015 (76%) groundball rates. It’s about impossible for teams to string together a bunch of groundball singles and avoid any double players.

The second major change is an increased use of his change (9% to 13%). He threw the pitch the 5th most in 2016 but now he’s using it the 3rd most often. The pitch is borderline elite with an 18% swinging strike rate and a 53% groundball rate.

With ERA estimators breaking down at the extreme ends of groundball rate, I am not surprised at all to see Keuchel’s ERA almost a point and a half lower than his ERA estimators.

Luis Perdomo (#5, 2.71 pERA): Perdomo is the first major surprise on the list. With no Wins and an ERA over 5.00, I can see why owners are shying away from the 24-year-old righty (35% ownership at FanTrax).

He’s got a ton of talent and many owners may not be have noticed yet. His overall groundball rate stands at 66%. Additionally, his most thrown pitches have a groundball rate over 55%. His curve (23%) and slider (17%) get an elite level of swinging strikes.

With all the groundballs, Perdomo should have an ERA significantly lower than his estimators. Perdomo “issue” is that his groundballs aren’t turning into outs (.336 BABIP). The Padres infield defense is letting him down with a league-worst -16 UZR infield defense rating.

The 2017 Padres will continue struggling to score runs. The infield defense is going to continue to struggle to make outs. So for 2017, I see no reason for Perdomo’s struggles to cease. He’s on the wrong team to utilize his groundball nature. In keeper/dynasty league, I like him depending on the cost. He’s Dallas Keuchel-lite and could be productive in the future.

Zack Godley (#8, 2.76 pERA) and Joe Biagini (#11, 2.83 pERA): I gave each pitcher a Quick Look recently and I still highly recommend them.

Tyler Skaggs (#9, 2.77 pERA): I’ll consider rostering Skaggs once he starts staying healthy.

Alex Wood (#10, 2.79 pERA): I feel dirty about writing something positive about Wood. It’s something I try not to do. Right now, Wood’s on the DL with shoulder issues. Before going on the DL, Wood was having his best season ever with a strikeout rate over 11, ground ball rate at 69%, and an ERA under two.

After looking over all of Wood’s information. His improvement comes down to throwing all his pitches 2 mph harder with a similar amount of break. Usually, when a pitch is thrown harder, the break amount drops because the pitch has less time to move between being release and crossing the plate.

With this new combination, he’s seen all of his pitch stats improve except for his change’s swinging strike rate.

Alex Wood: 2016 to 2017 Changes
Pitch 2016 2017 Change
GB% 2-Seam 46.8% 62.5% 15.7%
Change 60.0% 72.4% 12.4%
Curve 66.7% 73.1% 6.4%
SwStr% 2-Seam 3.7% 6.9% 3.2%
Change 17.0% 15.0% -2.0%
Curve 17.1% 20.0% 2.9%

Maintaining his velocity bump will be key to keeping his season going.

Mike Leake (#22, 3.18 pERA): A little BABIP luck (.318 in ’16 vs .234 in ’17) has helped Leake’s overall numbers. The key for his 2017 improvement is sort of hidden.

Here are is strike out related numbers from the past two seasons.

2016 6.37 K/9, 16.5% K%, 7.2% SwStr%
2017 6.36 K/9, 18.1% K%, 8.3% SwStr%

If owners only look at K/9, they will be disappointed with Leake, but he has bumped up his over strikeout rate which follows an increase in his swinging strike rate.





Jeff, one of the authors of the fantasy baseball guide,The Process, writes for RotoGraphs, The Hardball Times, Rotowire, Baseball America, and BaseballHQ. He has been nominated for two SABR Analytics Research Award for Contemporary Analysis and won it in 2013 in tandem with Bill Petti. He has won three FSWA Awards including on for his MASH series. In his first two seasons in Tout Wars, he's won the H2H league and mixed auction league. Follow him on Twitter @jeffwzimmerman.

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baltic wolf
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baltic wolf

Great stuff! Thanks!