A few days ago, Tyler Norton of Pinstripe Alley asked me for some thoughts about New York Yankees rookie Justus Sheffield. We wrote an article about Sheffield when he was promoted last week, which you can find here, but Tyler asked me to flesh that out a bit with some commentary about what Sheffield needed to do to prepare for a rotation role in 2019 or beyond.
First of all, the basic take in the original article still stands: Sheffield is one of the top left-handed pitching prospects in baseball, with MacKenzie Gore in the San Diego Padres system and Jesus Luzardo in the Oakland Athletics organization being the other competitors to the title.
Sheffield has three quality secondary pitches to go with a 90+ fastball, giving him an arsenal certainly diverse enough to start. While the Yankees used him in the bullpen in Triple-A in August, this was mainly to condition him for September MLB relief work. His track record of success as a starter in the minors is strong overall and I don’t think there’s a true durability question here, at least no more than for any young pitcher.
Overall, it boils down to consistency of command. This shows up in his K/BB ratio, 123/50 in 116 innings this year; the 50 walks is higher than ideal. When he’s going well, Sheffield keeps the ball relatively low in the zone; this clip shows some examples:
In contrast, when he’s having command troubles he can miss high in the zone and his secondary pitches become erratic; this showed up in his MLB debut last week against the Red Sox.
Sheffield admitted that he was nervous and that his adrenaline was pumping. That’s entirely understandable of course and should subside in time.
To prepare for a future starting role, I think Sheffield just needs to keep doing what he’s doing: use September to get used to the major league environment and quell any nerves, then head into spring training working to enhance command of his secondaries. It seems like a simple answer but it is an honest one.