Best/Worst Starting Pitchers According to ISO

ISO is used to determine a hitter’s ability to get extra-base hits as it is a measure of slugging percentage minus batting average.  So using the same idea and with the help of slugging percentage and batting average against we can evaluate the best pitchers at limiting extra-base hits.  First we will look a the 10 best starting pitchers in 2014 according to ISO.

PLAYER	ISO
Garrett Richards	0.069
Chris Sale	0.077
Felix Hernandez	0.083
Chris Archer	0.083
Sonny Gray	0.084
Adam Wainwright	0.089
Jose Quintana	0.089
Clayton Kershaw	0.092
Tyson Ross	0.093
Jarred Cosart	0.094

As would’ve been expected the top ten includes some of the best pitchers in the league.  Guys like Wainwright, Kershaw and many of the others are also found near the top of the ERA leader-boards.  However, one name more than the others does not quite fit with the others on this list, Jarred Cosart.  The hard throwing right-hander who was traded at the deadline from Houston to Miami has been one of the best pitchers in the league at limiting extra-base hits.  However, his ERA — 4.51 — does not match.

Cosart’s lack of success despite his ability to limit hitters to singles is due to two areas where he struggles.  The first is stranding runners.  Cosart’s LOB% of 67.4 is 9th worst in the league.  Although Cosart has excelled in mainly allowing singles he has not done a good job of keeping those hits from coming around to score.  However, the main area that Cosart has struggled this season is his control.  His BB% is tied with A.J. Burnett for third worst in the league at 10%.  Thus Cosart’s high frequency of baserunners due to his walk rate and his struggles in stranding runners have caused the hits he has allowed to do more damage.

Player	ISO
R.A. Dickey	0.174
Josh Beckett	0.175
Wei-Yin Chen	0.177
Edwin Jackson	0.177
John Danks	0.184
Chris Young	0.186
Eric Stults	0.188
Jake Peavy	0.191
Dan Haren	0.202
Marco Estrada	0.234

Again not surprisingly, several of these pitchers are among the worst qualifying starters in terms of ERA in 2014.  With the bottom 4 pitchers all with high-4 ERAs and Jackson pitching to a 5.66 ERA.  However, there are also a few outliers in terms of success with Beckett and Chris Young both pitching to much better ERAs than their ISO allowed would suggest.  Beckett’s 2.88 ERA is good for 19th best in the league with Young’s ERA placing him in the top 40 among starters.

Where both pitchers have succeeded this season is in stranding runners.  Beckett ranks number 1 in the league in LOB% while Young finds himself at 4th.  Both pitchers have been very successful at pitching themselves out of jams this season.  For that reason both pitchers have been able to allow a large amount of extra-base hits and still be among the best in the league at preventing runs.