On an otherwise quiet spring training day, the Dodgers made a transaction in order to increase their flexibility in forming the opening day bullpen. The Dodgers have claimed left-handed reliever Donnie Hart off waivers from the Orioles, and designated Josh Fields for assignment.
Fields was aiming to make the roster in his fourth season with the Dodgers after being acquired from the Astros in 2016 for now top-100 prospect Yordan Alvarez. Fields managed ERAs under 3 in the prior three seasons, but he never inspired confidence that matched those numbers. Thanks to particularly fly ball prone stuff, home runs were always a threat. 2018’s numbers were particularly alarming, as Fields missed fewer bats than ever and only 22% of the balls put in play against him were grounders.
As Dustin detailed earlier this week, Fields had the ability to refuse a minor league assignment, thus forcing the Dodgers’ hands in bullpen construction. Hart will bring additional flexibility with roster construction, as he has an option year remaining.
On the surface, the additional flexibility seems to be the most appealing thing about this transaction. Hart has a career DRA near 6 in 81 major league innings and posted an ERA of 5.6 last season. Hart is a side-arming lefty who averages 88mph with his primary pitch, a two-seam fastball. He compliments the fastball with a loopy slider and a changeup which only gets used against right-handed batters. For somebody with a sinker-heavy repertoire, Hart’s 52% ground ball rate doesn’t stick out very much. His profile based on his major league numbers isn’t very interesting.
Weirdly, though, Hart’s minor league numbers tell a different story. Combined across the last three seasons, Hart has a dismal strikeout rate of 15% in the majors. In the minors over that same span, he has a strikeout rate of 27%. Additionally, as you’d expect for somebody with a low arm slot, Hart has a big platoon split on his strikeout rate. In that three-year minor league span, he struck out 40% of the left-handed batters he faced. This seems like something that the Dodgers could take advantage of. The Orioles allowed Hart to face right-handed batters in nearly half of his MLB matchups, and better platoon protection would bring better results.
Hart’s splits bring back memories of the problems the Dodgers had constructing last year’s playoff bullpen. Scott Alexander has a relatively neutral natural platoon split due to throwing nearly all sinkers (his single-season numbers in 2018 had a higher split, but I don’t necessarily buy them due to how he pitches and his prior numbers). Caleb Ferguson also doesn’t seem to have a pitching pattern that would naturally produce large splits, since he doesn’t throw a slider. Alex Wood was gassed. Tony Cingrani was hurt. Alexander did not make the roster in the NLCS and was not particularly effective in the NLDS or World Series, which led to more use of Wood, which caused even bigger problems. The Dodgers would rather not relive that scenario.
If the Dodgers can figure out why Hart’s minor league success didn’t translate into the majors and use him strictly as a left-handed specialist, this could turn into an interesting transaction. In the meantime, due to Hart’s option, the Dodgers have some time to see what they have. It’s always possible that a scout saw something he liked and the Dodgers think they can “fix” him. It’s also possible that Hart will be gone in favor of a new waiver claim in a few weeks, continuing the roster churn where Farhan Zaidi left off. Either way, the Dodgers have some additional flexibility in building their bullpen in the weeks ahead, which is the main reason for this transaction in the first place.