A couple weeks ago, I looked into when to give up on hitters who struggle to start the season. (i.e. two months). It's now time to find the time to ditch pitchers who are struggling early in the season. In the end, walk and home-run rates are all that's needed with just a month's sample.
In 2021 drafts, both Lucas Giolito and Luis Castillo were early-round draft picks who struggled out of the gate. In April, Giolito had a 5.68 ERA while Steamer projections placed him as a 4.00 ERA guy. As for Castillo, he had a 6.28 ERA and 1.60 WHIP with an ERA projected to be around 3.50. Both pulled it together with Castillo having a 3.90 ERA in the second half and Giolito a 3.50 ERA over the same time frame.
On the other hand, Kyle Hendricks and Sonny Gray never did rebound from their early struggles. My goal was to find any indicators that pointed to the pitchers who have lost some talent compared to those who may have been unlucky.
To start the analysis, I took all the pitchers since 2010 who had their ERA a full run (1.00) above their preseason Steamer projection. Then, I compared how these pitchers performed over the rest of the season, looking for any common traits for those who struggled and those who regressed back to their projection.
After cutting and dicing the data several ways, two common traits stood out: a jump in walk and home-run rates.