10 October 2016

How Zach Britton "Struggled" In 2016

Zach Britton, with a 0.54 ERA and a perfect 47 for 47 in save opportunities, had a pretty decent year in 2016. As noted by Steve Melewski, Britton is one of three pitchers in major league history to have at least 40 saves and an ERA below 1. At one point of the season, Britton went nearly four months without allowing an earned run. So, the obvious question is how much of his performance was luck and whether he can maintain these results in 2017.

Obviously, to do what Britton did in 2016, a pitcher needs to be dominant. But what’s interesting is that Britton held opposing left handed batters to a .495 OPS (.185/.254/.241) and right handed batters to a .410 OPS (.155/.211/.199). In addition, Britton had a K% of 26.7% and a BB% of 8.3% against left handed batters, but a 29.9% K% and a 6.7% BB% against right handed batters. This is surprising because normally a left handed reliever does better against left handed batters than right handed batters.

In fact, Britton easily had his worst year against left handed batters since he became a reliever. In 2015, he held batters to a .145/.181/.145 line with a 40.3% K-rate and a 4.2% BB-rate. In 2014, he held these batters to a .170/.215/.170 line with a 23.7% K-rate and a 5.4% BB-rate. And after not allowing a single extra base hit to a left handed batter in either 2014 or 2015, Britton allowed 3 doubles to lefties in 2016, 2 of which (including a ground-rule double) were hit by Brad Miller of the Rays.

Part of his problem against left handed hitters was his high walk rate. Left handed hitters struggle against him, even when putting the ball into play, so he doesn’t need to worry about giving up contact. But he still had a “poor year” in 2016 against lefties when they put the ball into play. Left handed hitters had a .267/.267/.333 line against him when putting pitches in the strike zone into play compared to an OPS of .452 in 2015 and .483 in 2014. His rank was 21st out of 216 relievers that appeared in 30 or more games. In 2015, he ranked 5th out of 218 and in 2014 ranked 6th out of 203.

He also had some poor luck against lefties when they put pitches out of the strike zone into play. Opposing batters went 2 for 8 against Britton with a single and a double in 2016 good for 93rd out of 215 relievers. Given Britton’s dominance against lefties, this is pretty surprising. Given the small sample size, this is almost certainly just random luck.

Some of the blame for Britton’s relatively high walk rate to left handed batters is due to his sinker. Britton only threw 45.7% of them in the zone in 2016 compared to 48.7% in 2015 and 64.1% in 2014. Opposing batters had a good eye when deciding not to swing at these sinkers as they had a called ball rate of 33.1% and a called strike rate of 14%. In 2014 and 2015, Britton’s sinker was a called ball 30% of the time and a called strike 21% of the time. This chart shows its results.

However, the bigger problem was his slider. Left handed batters only swung at 7 of his 31 sliders, missing 5 of them, fouling off another and putting only one into play. However, of the other 24, 17 resulted in called balls while 7 were called strikes. In 2015, batters swung at 14 of 29 sliders and missed 10 of them. Of the 15 they didn’t swing at, 8 resulted in called balls while 7 resulted in called strikes. Without a successful slider to keep batters honest, Britton wasn’t able to maintain his high strikeout rate of 2015. Britton’s slider is devastating, even when thrown inside the strike zone and perhaps he should consider trying to throw it in the strike zone more often. This graph shows the results.

If Britton had a “poor” year against lefties, he made up for it with his performance against right handed hitters. Right handed batters had a .250/.250/320 line when putting pitches in the strike zone into play in 2016, compared to a .350/.350/.510 in 2015 and a .250/.250/.426 in 2014. In addition, Britton allowed a .130/.130/.174 line to right handed batters when putting pitches out of the strike zone into play, compared to a .316/.316/.388 in 2015 and an .182/.182/.182 line in 2014. Right handed batters may have had success against Britton in 2015, but they sure struggled in 2014 and 2016.

Britton also had some improvement in his strikeout rates. In 2016, Britton had a 29.9% K-Rate and a 6.7% walk rate. In 2015, he had a 27.6% K-Rate and a 6.1% walk rate while in 2014 he had a 20.8% K-Rate and a 9.4% walk rate. Clearly, he’s showing some progression. Part of the reason for it is that Britton’s sinker against righties was a bit nastier this year than in years past. Batters put a lower percentage of his sinkers into play, and therefore gave Britton more chances to strike them out.

Going forward, Britton is very good against right handed batters. He’ll put up strong strikeout and walk percentages against right handed batters, but he’ll need to do an excellent job preventing damage on balls put into play in order to put up elite numbers against right handers. To be fair, it’s awfully hard for even right handed batters to do anything more than just ground out. However, he has it in him to be absolutely otherworldly against left handed batters. All he needs is a bit better luck on balls put into play, and the ability to either get them to swing at his slider or put a few more in the strike zone. It’s likely that we should expect some regression from Zach because I suspect right handed batters will have more luck against him next year. I’d expect to see him have an ERA in the low to mid 1s range next year.

The average pitcher had a .350 OPS last season when batting. If Britton can put together his 2016 season against right handed batters with his 2015 season against left handed batters, then opposing hitters might not break that .350 OPS mark. If so, he’ll almost certainly have another excellent season and might possibly improve on his 2016.

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