We’re officially on a self-proclaimed Heater. Let’s keep it going today, shall we?
Of the 2 early games, I’m targeting STL/KC for the pitching matchup between Zack Greinke (0-1, 2.86) and Steven Matz (2-1, 6.11).
I’ve mentioned in past articles that I believe Earned Runs Average (ERA) is a misleading stat. All it takes is one bad inning to stain the number. It can also be skewed high or low by factors out of pitchers’ control like ballpark dimensions, weather, defense, etc.
Rather than look at ERA, I prefer MLB Statcast’s expected Earned Runs Average (xERA), which attempts to adjust for some of those things. It’s measured based on quality of contact (i.e. when the bat hits the ball) rather than actual game outcomes. The idea being that allowing good contact will eventually bleed through to your stats in the form of more earned runs.
Applied to this game, I see:
- Royals’ pitcher Zack Greinke has a 2.86 ERA (good) but much worse 6.07 xERA, indicating some negative regression could be imminent.
- Conversely, I see Cardinals’ pitcher Steven Matz has a 6.11 ERA (bad) but a 4.38 xERA (still not great, but better than 6.11).