Starting Pitcher Workloads Have Been Significantly Reduced in 2020

Already what sticks out is that this year, for the first time, starters are averaging fewer than five innings per turn, and their per-start average is down more than one full inning since 2015. What’s more, if this trend continues, it would be the biggest year-to-year drop in innings per start in the span, more than double the drop from 2018-19, and more than triple the other year-to-year drops within that span.

Over the years, a number of factors have driven that decrease, starting with deeper pitch counts, which are a byproduct of higher strikeout rates, as you can see in the table. There’s also the increased understanding of a few sabermetric concepts: starters are generally less effective facing batters for the third time in the game than prior; relievers are generally more effective facing batters for the first time than starters are in any of those appearances; and batters are less effective when they lack the platoon advantage. As starters’ workloads have decreased to account for those factors, their run prevention relative to the league has improved ever so slightly.