Following the David Peterson trade, Zach Thornton is expected to be called up to join the rotation on Thursday. Thornton has a 4.25 ERA and 1.42 WHIP in 55 minor league innings this year.
Thornton throws eight different pitches, and in the minors, his fastball has been his most used pitch, coming in at 31.5%. He has shown flashes of a plus fastball at times, topping out at 95.7 miles per hour and hitting as high as 21.7 inches of induced vertical break, but those have been few and far between. He has averaged 92 miles per hour and 17.5 inches of iVB. If he can find any consistency in his stuff, he could raise his ceiling more than the up-and-down depth pitcher he currently is.
Thornton’s biggest asset is his ability to throw strikes, but he does not have swing-and-miss stuff, so that can still lead to long at-bats. He has only pitched into the sixth inning four times this year. But the current bar to improve upon is being better than either Kodai Senga‘s 10.08 ERA or David Peterson’s 6.09 ERA. Preseason projections had Thornton hovering around a 4.70 ERA and 1.35 WHIP.
The Mets have placed second baseman Marcus Semien on the injured list with a hip flexor strain. This season has been a struggle for Semien, who has slashed .214/.271/.341/.613 while also struggling defensively. After his worst defensive game of the season, it would not be shocking if he has not been fully healthy. Semien has vastly underperformed his metrics this year.
Infielder Ronny Mauricio has been called up to replace Semien, though it is unclear if he or Brett Baty will take the bulk of time at second base. Mauricio has performed well against right-handed pitching in his career in the majors thus far, slashing .272/.332/.423/.754 across 232 PA. Against left-handed pitching, he has only hit .136/.174/.193 in 92 PA. He has not looked any better in Triple-A, with an 11th percentile 75% zone contact rate against left-handed pitching this season. Brett Baty is not any better of an option against lefties: he has slashed .163/.265/.233 against them this season.
Semien has slashed .250/.321/.347/.668 against left-handed pitching so far this year, and while that is not amazing, it is roughly league average and a step above what you would expect from Mauricio and Baty. This causes a big question mark for how they will handle facing left-handed pitching, but with the Mets facing lefty Matthew Boyd today, we will not have to wait long to see what they decide to do.
The best move may be to try Bo Bichette at second base and put Eric Wagaman at third base, but with Bichette finally hitting and looking good defensively at third base, I could understand why the Mets might be hesitant to try him at another new position.
At the very least, the Mets are getting some new blood in the rotation and lineup, and they could use all the help they can get.
