Michael Pineda had completed five strong innings for the Twins on Tuesday, at which point Minnesota held a slim 2-1 lead against the White Sox. He had thrown 89 pitches and had good enough stuff to strike out eight batters while allowing just four hits.
A few years ago, Pineda might have been asked to pitch at least another inning. Another generation or two ago, seven innings would have been the expectation — regardless of Pineda’s injury history or other circumstances.
But on Tuesday, five innings and 89 pitches was it. Maybe it wasn’t enough to mollify baseball purists who like to see starters work deeper in games, but it was a modern masterpiece of sorts.
It also was a good example of how a 5-inning effort from a starting pitcher isn’t really indicative of any sort of weakness on the part of pitchers these days. Rather, outings like that are becoming the norm thanks to a series of circumstances and strategic changes.
*As of 2014, per The Ringer, the average starting pitcher went about 6 innings — around where it had been for two decades. In the 1960s and 1970s, it was more like seven innings. This year, the number is 5.25 innings. That’s skewed a little by the use of “openers” and bullpen games, but most of it comes from traditional starts.
But consider this: In 1988, for example, the average plate appearance lasted 3.58 pitches. This season, it’s 3.93 plate appearances as batters work deeper into counts while hunting walks and not fearing strikeouts. Over the course of an average 6 inning start, that adds about 9-10 pitches to a starter’s workload — helping partly explain how innings pitched are going down.
*Pitchers are throwing harder than ever, but they’re also throwing fewer fastballs.
Per FanGraphs, starting pitchers threw fastballs about 57% of the time a decade ago. That number now has dipped to more like 52%. Average fastball velocity, meanwhile, has jumped from just above 90 mph for starters a decade ago to more like 92 mph now.
As FanGraphs notes, that’s largely in response to higher home run rates: Batters slugged .441 against fastballs in 2015 and .359 against everything else. When every little dinky fly ball starts turning into a home run, it’s only natural to start throwing a few more breaking pitches.
Throwing harder likely means pitchers get tired more quickly. Breaking balls also involve both wear-and-tear and deeper counts since fastballs have a slightly higher strike percentage than breaking balls. Even with Pineda pounding the strike zone (60 of 89 strikes) on Tuesday, it took him a lot of pitches to get through five innings (including 29 in the fourth inning, which likely sealed his five-inning fate).
*There’s not much data that I can find on this, but I’m also of the mind that modern starting pitchers face more high-leverage innings than they used to for two reasons: Lineups are stacked deeper with more power hitters, so there are fewer “easy” innings. And more teams are in playoff contention deeper into seasons thanks to the evolution over time from one to five teams from each league that make the postseason, meaning more games matter.
*There IS data, however, on what happens to pitchers when they face a hitters for a third time in a game. This year, for instance, batters have a .724 OPS in their first plate appearance vs. a starting pitcher, but that increases to .780 the second time and .799 the third time. Hitters are smart and can adjust by then.
Pitchers are wearing down. Why not go to the bullpen? There’s a whole crew of fresh arms down there, ready to throw even harder than starters while only giving batters one look (usually) per game.
That’s what the Twins did Tuesday, getting a single scoreless inning from four different relievers in a 3-1 win. That they used five pitchers is hardly unusual; teams on average are using 4.27 pitchers per game this season, way up from previous generations.
It’s not wrong. It’s just different — and explainable once you really examine it.