Sheffield showed no ill effects from his stay on the DL for a strained oblique dating back to July 6, using his fastball aggressively in a pitch-count-shortened, three-inning start on September 3 versus Reading. Working with tight and repeatable mechanics from his filled-out 200-pound frame, Sheffield’s plus fastball was in the 92-to-95 mph range (T96) and sitting mostly 95 mph in this shortened stint, with some two-seam tail in the lower range, and some ride up in the zone as he challenged hitters early and often. His command of the fastball wasn’t dialed-in, and a few misses left up in the zone were the primary culprit for his five hits allowed, but he did not walk a batter in the outing, and he controlled all four of his pitches well.
Sheffield ‘s above-average and hard slider showed 3/4’s depth and bite in the 85-to-89 mph range. He was effective in getting lefties to chase it out of the zone for putaway while also adding and subtracting from it. He threw just a few average curveballs at 83 mph, and they came in with more hump than the slider with 1-to-7 shape and tight spin, and shape is distinct enough to separate it from the slider and give him some deception in his breaking stuff. His changeup was also above-average, coming in firm with late dive in the 86-to-87 mph range, and it’s fastball look out of hand had bats swinging over the top of it.
While the outing was short at just 54 pitches, it looked like all systems were go for Sheffield to pick up where he left off in July, and he’ll be heading to the Arizona Fall League to make up for innings lost to the disabled list this year. His control numbers came down to fringe average (3.1 BB/9, from 3.8 last year) and with his refined mechanics and quick tempo, those numbers could improve a grade – or two – as he matures, even with the moderate effort he has in the delivery. Still pitching in just his age-21 season, his ceiling of a Role 60 mid-rotation starter looks realistic at this point. He could find himself in Triple-A Scranton/Wilkes-Barre after a few starts at Trenton to start his 2018 season with confidence.