When the White Sox announced last week that Chris Sale’s next start would be skipped due to what he described as a “dead arm,” fans’ stomachs turned. Sale has been incredible this season, at the time of his skipped start he was carrying a 2.61 ERA, striking out almost a batter an inning (0.92 K/IP), and limiting batters to just a .214 batting average against him. He has a case as the best pitcher in baseball this year and has certainly been among the top five.
He had also pitched 124 innings at that point, far more than his previous professional high of 71. Team usually try to avoid allowing young pitchers to add more than ~50 innings per season, because more than that is viewed by many as too dangerous a strain on their still developing arms. If the White Sox weren’t in contention, I think there’s a good chance Sale would have been shut down for the year when he reported the soreness last week, but with the team in a heated A.L. Central race, they sent him back to the mound last night. How did he respond? By throwing 8 innings, striking out 7, walking none, and giving up just 2 runs (on two solo home runs, which is the first time he’s given up two HR in a game). He is now 61 innings above his previous high, but still looks quite dominant.
I can’t blame the Sox for putting him back in the mix; the two or three additional wins Sale might provide could easily be the difference between making the playoffs and going home. Still, I was curious about how other young pitchers have done, once they’ve exceeded their previous high in innings, so I set out to do some research and see what I could find.
First, with some help from Baseball-Reference, I created a database of every pitcher in the last twenty years, 24 years old or younger, who threw at least 120 innings, with an ERA that was at least league average (as measured by ERA+, in which 100 represents the league average). There were 246 such seasons to examine.
Then, I went through those seasons to see how each and every one of them compared to the pitcher’s previous workload. The chart below is every one of the pitchers from that 246 who exceeded his previous high in innings pitched by 50 or more (note: “professional” innings, meaning both Major and Minor League, but not collegiate) and then made at least two more starts (because I want to see the track record for pitchers doing what Sale will be doing as he goes forward).
PH stands for “previous high.” Change is the amount of additional innings they pitched. The date listed is when they reached 50 innings above their PH. Then, the number of starts they made after reaching that point, their ERA through that start, and their ERA after that point.
Previous High (PH)
Date PH +50 IP reached
ERA through PH +50 IP
ERA rest of season
As you can see, there simply aren’t that many pitchers who’ve made the kind of jump Sale is in the midst of, just 15 in twenty years and only 5 in the last ten years. 9 of the 15 pitchers saw a rise in their ERA after hitting the PH +50 mark, but most of those jumps were very small and came in a very small sample size, because only 5 of the 15 pitchers listed made more than four starts after reaching the PH +50 threshold. The Sox will be hoping Sale can make another 8-10 during the regular season, so Hermanson, Rupe, Weaver, Lincecum, and Leake are the only pitchers I found who really made the sort of innings jump Sale is aimed toward. Hermanson, Rupe, and Lincecum all actually improved their performance after the PH +50 mark and while Weaver’s ERA shot up in those final 11 starts, it was still a very strong 3.38. Only Leake had a poor ERA after the mark, and he skipped the minors entirely after a lengthy holdout between his being drafted and his debut.
In the end, the data above isn’t enough to draw strong conclusions from. My main take away will be that Sale is doing something that simply isn’t done very much, especially over the last decade. But, what little track record exists for pitchers doing this isn’t bad looking. Jered Weaver’s numbers, both in terms of his previous PH and his performance up to the PH +50 mark, are the closest to Sale’s, and I think Sox fans would be happy to get 11 starts and a 3.38 ERA the rest of the way from Sale (and would be thrilled if his 2013-2018 go as well as Weaver’s 2007-2012).
The Sox should keep a close eye on Sale, pull him early when possible, even if he’s pitching well, and skip his start a couple more times to give him added rest and recovery, but I don’t believe they need to pull the plug on his season unless he shows or reports signs of being overtaxed.