Marlins Officially Pull Plug on Failed Rotation Experiment

The Miami Marlins are making a change to their rotation

The Miami Marlins are getting healthier. 

Plagued by injuries to both their rotation and position player corps this season, the team’s already starting to get some good news with the returns of Edward Cabrera (shoulder) to the rotation and catcher Christian Bethancourt (illness) to the lineup. 

And because there are more options now than there was a few weeks ago, the Marlins can finally correct a failed experiment - starter A.J. Puk, who was moved into the rotation this season after multiple years as a reliever, is going back to the bullpen once he’s activated off of the injured list. 

Puk, who turns 29 today, made the first four starts of his five-year major league career to open the 2024 season. They didn’t go particularly well, with Puk amassing a 0-4 record and 9.22 ERA in just 13.2 innings. He gave up seventeen runs (14 earned) in those innings, with just 12 strikeouts. 

It’s honestly surprising how poorly things went for the lefty. His career ERA as a reliever is only 3.72, but that almost tripled when he began covering multiple innings to open games. His walk rate also exploded, from a career 3.6 BB/9 as a reliever to sitting at 11.2 after walking seventeen batters this season. 

While a slight reduction in his strikeout rate was expected, going from 11.2 as a back-end relief option to 7.9 as a starter shows how much his ‘stuff’ regressed - Puk went from averaging 95.8 on his fastball and backing it up with a mid-80s sweeper to only 93.3 on the heater, a reduction of 2.5 mph. The batting average allowed on Puk’s sinker skyrocketed from .273 to .545, and hitters have already slugged .909 on the pitch. 

Two other converted relievers, Jordan Hicks of the San Francisco Giants and Reynaldo López of the Atlanta Braves, have had their transitions go much more smoothly, with the two among MLB’s top ten in ERA as of Thursday morning. 

Puk, currently on the injured list for “shoulder fatigue”, is expected to resume working in the back end of the Marlins bullpen once he’s healthy. It’ll be a welcome addition to a beleaguered Miami relief corps that’s already had to cover 102.2 innings this season and done it at a 4.73 ERA. Miami’s bullpen is middle of the pack in WAR, sitting at -0.4, have already taken on nine losses and converted just 36% of their save opportunities.