Red Sox grade: C-
May was a key pitcher on the 2020 World Series championship team for the Dodgers, but pitched just 101 innings over the next four seasons before returning this year and posting a 4.85 ERA in 18 starts. As the ERA suggests, he hasn't been too effective, with both a high home run rate and a high walk rate. He doesn't throw as hard as he did back in 2020, and that shows up in how hard his sinker has been hit this season (.285 average and .633 slugging percentage).
May is heading into free agency, so this doesn't even fit the idea of "let's get him this season and maybe he'll be better next year as he's further removed from surgery." He can join the rotation in place of Richard Fitts or even a mediocre Walker Buehler, or maybe he goes to the bullpen, where his fastball might play up a little better.