At the late July trade deadline, the Yankees aimed to strengthen their roster with three significant acquisitions. Jazz Chisholm has been a standout addition, excelling both offensively and at third base. However, the bullpen additions have not fared as well. Enyel De Los Santos was released after struggling for months, underscoring the Yankees’ challenges in enhancing their relief pitching this season.
Mark Leiter Jr., the other bullpen acquisition, has had a rocky start but is beginning to show promise. Prior to the trade from the Chicago Cubs, Leiter had a 4.21 ERA over 36.1 innings, with metrics indicating potential for improvement. Unfortunately, since joining the Yankees, he has struggled, posting a 5.68 ERA over 19 innings, with 2.84 runs allowed per nine innings—unsustainable for a dependable reliever. Despite these issues, he has maintained an impressive strikeout rate of 12.79 strikeouts per nine innings. However, his ground ball percentage has significantly dropped, adding to his struggles.
Notably, Leiter’s advanced metrics remain encouraging, placing him in the 96th percentile for chase rate, 97th for whiff rate, and 95th for strikeout rate. This suggests he has the potential to be an asset, but pitch location has led to hard contact from hitters.
A major concern has been his sinker, which has allowed a .394 batting average and a .620 slugging percentage, averaging just 91.5 mph. In contrast, his split-finger fastball and curveball have been performing exceptionally well. The Yankees have responded by reducing his sinker usage; in September, he relied on it only 13.7% of the time, down from 31.9% in August. Instead, he focused on his split-finger fastball and curveball, leading to a strong outing against the Oakland Athletics where he recorded three strikeouts in two innings with minimal sinker usage.
