Young left-hander Madison Bumgarner is having a fantastic season so far. His strikeout rate is the highest it's ever been, and his walk rate has lowered back down to career norms after a 2013 spike. Here is his stat line to date. It's very pretty, filled with things that look sustainable, except maybe the high BABIP. That would work in his favor. His ERA almost exactly matches his xFIP. I find satisfaction when peripherals line up like this.
With an increase in his K-BB%, and a decrease in FIP and xFIP, I would like to investigate if Bumgarner has made any changes this year. We always like to find causes for improvements like this because we want to believe the improvement is sustainable. If we can find a cause, improvement is more likely to be sustainable. With FanGraphs' new heatmaps, we can delve further to see how Bumgarner is attacking hitters differently, if at all.
First, against left handed hitters, it seems like Bumgarner is attacking the up and in part of the zone more than average (left handed pitchers only) this year. However, it is a fairly small sample. Looking at this data year by year shows that Bumgarner has steadily increased his usage of that area of the zone against lefties, and his wOBA against for lefties has decreased each year until 2014. The runs above average version of the above heatmaps shows that Bumgarner's RAA/100P is better in the up and in part of the zone than league average. It would appear that Bumgarner has great success against left handed hitters by attacking up and in.
What about against right handed hitters? Bumgarner does significantly worse against right handed batters for his career (.256 LHB wOBA vs. .298 RHB wOBA). Worse is relative, though, as he still is dangerous against righties. What is his strategy against RHB?
Most left handed pitchers try to stay low and away against right handed batters. Bumgarner does not. He attacks right handed batters up and at both sides of the plate, at least in 2014. There is another trend happening here; Bumgarner used to use the lower part of the zone more and the upper part less, and there has been a corresponding decrease in GB% as he has used the upper part of the zone more. How has this worked out for him?
It looks like Bumgarner is achieving success when attacking the upper part of the zone against right handed batters. When he does go low and away, it looks like Bumgarner gets punished when the pitch is out of the zone. Overall, the strategy seems to be working well for him. His wOBA against for right handed batters has also decreased each year until this year. The following tables show his wOBA against through the years against both left handed batters and right handed batters with some other stats thrown in to see how his evolution has affected his performance.
Mr. Bumgarner knows what he's doing; against right handers, he's defying the conventional "low and away" philosophy and having great success by working the upper part of the zone to both sides of the plate. He's employing a similar strategy as Chris Young, whom Eno Sarris detailed at FanGraphs. If I were a left handed hitter, I would go up to the batter's box, tip my helmet, and sit back down. The 2014 wOBA hasn't come down just yet, but that could be related to the high BABIP he's running. The K-BB% is at a career high against both handed batters. Bumgarner's evolution of how he has attacked hitters looks like it is at least partially responsible for his improvement in performance, and perhaps some of this new level of performance is sustainable. Signed to a team-friendly contract, Bumgarner is one of the best young pitching assets in the game.
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All statistics courtesy of FanGraphs.