Chris Sale is worse under pressure this year

Clutch pitching is a tricky concept. It definitely differs from clutch hitting — whereas luck and random variation account for virtually all of the latter, the former has some skill behind it. We know, for instance, that elite pitchers tend to excel in tough spots, while poor pitchers generally shrivel in those situations. At the same time, pitchers who strand a lot of runners probably benefit from good fortune, and vice versa. Here, separating the signal from the noise becomes crucial to determining the sustainability of a pitcher's situational performance.

Chris Sale has been one of the best pitchers in the world for a few years now. A largely unknown aspect of his dominance: his ability to pitch better with runners on. From his debut in 2010 to his superb 2014, Sale stranded 79.9% of the runners who reached base against him, the sixth-highest mark in baseball. His 2.9 LOB-Wins, meanwhile, moved him up to fifth. In short, Sale — like many hurlers of his quality — more than proved his mettle.

Surprisingly, then, he's struggled to prevent runners from scoring in 2015. His LOB% has plunged to 70.8%, 68th in the majors; that drop has cost him 0.9 wins, which only nine other pitchers can beat. What has happened to spark this devolution? Should we attribute this to the natural fluctuations of the game, or to a legitimate alteration on Sale's part?

Let's first look at his wOBA split, along with some other statistics, for the aforementioned five-year span. These reveal an interesting trend:

Across those seasons, Sale did better by every measure (save long balls) with runners on base. Now, let's see those numbers for 2015:

(Note: Data not park-adjusted.)

Here, two things stand out. Sale has pitched better than before when no one has reached base but worse than before when someone stands behind him. Put those two together, and you get a pitcher who's gone from clutch to a choker.

Let's start from the beginning — i.e., Sale's first five seasons. In those years, he used his pitches differently based on the situation (per Brooks Baseball):

Sale's devastating slider, the pitch on which he retired most batters during that time, saw more action when the going got tough, replacing his generally inferior four seamer and sinker. Thus, he posted slightly better results in those predicaments, which helped him leave runners on base.

But Sale didn't continue banking on that slider. Out of concern for his health (since heavy use of the pitch may lead to injury), he phased it out of his repertoire in favor of his still-exquisite changeup. 2015 has seen him throw the cambio 29.4% of the time compared to only 16.0% sliders. With this as his new out pitch, Sale's probably thrown it more heavily in the important situations, right?

Oddly enough, he hasn't:

Unlike in prior campaigns, Sale has relied on his hard stuff in difficult circumstances. While the four seamer has done fairly well for him over his career, it's never reached the level of his slider or changeup; for that reason, he's struggled out of the stretch.

Why has Sale modified his approach with runners on? I really can't say — it doesn't make much sense to me that he'd throw fewer changeups, his best pitch. Neverthless, this is how things have gone so far, and if he keeps this up, the runners will probably continue coming around against him,

For the rest of the season, FanGraphs projects Sale to put up a 77.5% LOB. As he takes the mound tomorrow night to face the Cardinals, we'll see if he starts to turn this around. For now, though, he's lost his ability to strand most of the runners who reach. Random variation can often play a role with these types of statistics, but this represents an instance where the pitcher deserves the blame.

. . .

All data as of Monday, June 29th, 2015.

Ryan Romano is an editor for Beyond the Box Score. He also writes about the Orioles on Camden Depot (and on Camden Chat that one time), and about the Brewers on BP Milwaukee. Follow him on Twitter at @triple_r_ if you enjoy angry tweets about Maryland sports.