The Red Sox acquired left-handed pitcher Drew Pomeranz from the San Diego Padres halfway through 2016, in exchange for promising A-ball pitcher Anderson Espinoza. Pomeranz was pitching like an ace for San Diego (2.47 ERA, 1.059 WHIP in 17 games), but was pretty bad after the trade. For Boston, in the regular season, he had a 4.59 ERA and a 1.369 WHIP in 14 games (including one relief appearance), and followed that with two even worse relief appearances in the ALDS (four hits and two walks in 3.2 innings for a 4.91 ERA and a 1.636 WHIP in 2 games).
Although Pomeranz was ostensibly not injured in the second half of the season, San Diego was penalized for hiding medical information about him, raising concerns about possible underlying health issues that might explain his struggles in Boston. In the offseason, Pomeranz received stem-cell injections in his elbow to treat what he called “discomfort.” Even assuming good health, Pomeranz’s role in 2017 after David Price comes back from the disabled list is not yet clear; he has major-league experience both as a starter and a reliever, and could find himself the odd man out despite his protestations.
What he throws: Pomeranz throws a four-seam fastball (“FF”), cutter (“FC”), curve (“CU”) and changeup (“CH”). His fastball is not particularly fast, averaging 91.2 mph in San Diego and 91.4 mph as a starter in Boston:
Pitch usage and trends: Pomeranz’s main pitches are his four-seam fastball and his curve. He also occasionally throws a changeup (7% of pitches). He had very small platoon splits in 2016; right-handed batters had a .663 OPS against him, and lefties had a .643 OPS. His pitch usage to left- and right-handed batters is very similar, with the exception of his changeup, which he mainly used against right-handed batters and when behind in the count. He used his curve more when ahead in the count than when behind. His repertoire was similar in San Diego and Boston, although he used the changeup slightly less in Boston (4.8% vs. 8.5% in San Diego):
Pomeranz only added the cutter to his repertoire in 2016, and took a half-dozen games before he really started to include it in game situations. He almost gave up on it again at the end of the season, barely using it for his final two starts (Sept. 18 and 23). His last three appearances of 2016 (including two in the postseason) were in relief, and only one of the 102 pitches he threw was a cutter. (In the charts below, the vertical blue line indicates the point when he was traded from San Diego to Boston.) In his three relief appearances (including the postseason), he threw considerably harder, averaging 93.4 mph and reaching a maximum of 96.0 mph vs. 94.8 as a starter. He maintained his velocity well over the season, showing no signs of injury as far as that goes:
Pitch value. Over the entire season, Pomeranz’s most effective pitch (based on total bases per 100 pitches) was his changeup, which he essentially used only against right-handed batters. On the other hand, he didn’t throw it for strikes, which helps explain why it wasn’t hit very much; he averaged 47.5 balls per 100 pitches with it, compared to the league average for changeups of 37.7. His fastball was better than league average against lefties but worse against right-handed batters, while his cutter was the opposite. His curve was slightly better than league average against both sides of the plate:
The move to Boston drastically affected all of Pomeranz’s pitches, with all of them dropping significantly in effectiveness. Only his changeup remained better than league average in terms of TB/100, but it became even worse with regard to strike percentage, dropping from 43.4 B/100 in San Diego to a terrible 58.2 in Boston:
Pitch location. Without an overwhelming fastball, Pomeranz relies on locating his pitches for success. Each of his pitches typically does a good job of hitting the edges of the strike zone. His fastball and cutter in particular were often either just at or just inside the zone, while his curve and change were more likely to end up outside, but still averaged to be just at the edges:
Comparing pitch locations into his San Diego and Boston tenures shows some differences that suggest a loss of command. His fastball locations were similar, but especially to left-handed batters the fastball was closer to the middle of the plate on average. His curve to left-handed batters also was more likely to be in the center of the plate, as was his cutter to righties: