The Most Vulnerable Rotations in MLB
Every team starts the season with five starters, but the chances a team makes it through the season unscathed is minimal. From research performed by Jeff Zimmerman, starting pitchers who made 20 starts and pitched 120 innings the previous season have roughly a 40% chance of hitting the disabled list during the season. Eno Sarris added to Zimmerman’s work before the start of last season and found that teams have been averaging around 10 starters per season since 2011. That average did not change last season as teams averaged 9.6 starters per team. Even if the bar is raised to a minimum of five starts, teams averaged 7.4 starters per team in 2014, consistent with five-year average of 7.5 starters per team per season.
Attempting to measure pitching depth can be difficult. Jeff Sullivan took a look at overall depth last month, showing how many players were projected for at least one win according projections. Focusing on rotation depth the same way is a good way to look strictly at depth, but with the season upon us, we can see the potential impact of that depth by examining the dropoff from starters to their replacements. FanGraphs completed the Positional Power Rankings with the pitching split into two posts, one for the bottom half, and one for the top half. Without rehashing the entirety of both posts, here is the graph from those posts which should provide a base of expectations for a team’s rotation.
Read the rest of this entry »