MLB: How baseball has changed over the decade
By Bill Felber
Pitcher usage
In 2009, the last year of the previous decade, 117 MLB pitchers started at least 20 games. They were, in other words, rotation regulars. Over the century’s second decade, the number of pitchers employed primarily as starters hardly moved at all; 113 made 20 or more starts in 2019.
But if the ranks of starters remained roughly the same, reliance on those starters decreased sharply. In 2009, those 117 pitchers covered an average workload of 176.8 innings per pitcher, or about one-half the 1,400 innings required of a team over the course of a 162-game season.
By 2019, that same cadre of starters covered an average of just 161.8 innings, nearly a 10 percent reduction in starter workload over the course of the decade.
In 2009, Detroit’s Justin Verlander was the game’s premier workhorse, covering 240 innings. The 10 most heavily used starters averaged about 232 innings.
In 2019, Verlander – now with Houston – remained the game’s hardest-working pitcher…but with 223 innings, about seven percent fewer. The 10 hardest workers averaged just 211 innings, a nine percent decline in workload.
The disbursed workload worked its way all through the staff. By 2019, teams were averaging 18.2 pitchers with at least 20 innings of work, two more bodies more than a decade earlier. Yet fewer pitchers worked 75 and 125 innings in 2019. This season 62 pitchers delivered the minimum 162 innings required to qualify for consideration for the ERA title; a decade earlier, 79 pitchers reached that threshold.