Introduction
Undoubtedly, it has been a fun couple of weeks for the Diamondbacks. They’re tied for the second-best record in the majors over their last 20 games at 14-6, they’ve batted to a .248/.323/.382 slash line, and pitched to a 2.59 ERA. Those results find the team seven games over .500 and have watched their Baseball Reference playoff odds spike by nearly 30% over the last month and their Fangraph’s odds increasing by almost 18%. One part of that stretch that shouldn’t be lost in the exciting shuffle:
just how good the starting rotation has been this month as they’ve pitched to a 3.03 ERA and 1.074 WHIP while averaging over six innings pitched per game. That kind of length has limited the bullpen’s exposure to just 63.1 IP for the month compared to 116.1 IP in the first month of the season. That lack of usage has particularly hurt Brandon Pfaadt who hasn’t appeared in nearly a week and has struggled to be as impactful as he was last year when he was second on the team in innings pitched while making 33 starts. As part of that dynamic, there has been plenty of musing on and off the air on what kind of role Pfaadt will play in the pitching staff moving forward, especially as several players slowly but surely make their way back from injury including AJ Puk and Justin Martinez. What can the team do and what kind of role will he have moving forward?
Roster Crunch
This was always likely to be a problem for Pfaadt with the offseason signing of Michael Soroka and the re-signings of both Merrill Kelly and Zac Gallen gave the team six viable starting pitchers before including the eventual return of Corbin Burnes sometime around the All-Star Break. The team did give Pfaadt a brief opportunity in the rotation while Kelly was working his way back from injury at the beginning of the season, but the results were not very encouraging, prompting the team to move Pfaadt into the bullpen as a multi-inning reliever instead. There’s certainly some successful precedent to the move as players like Tommy Henry and even Ryne Nelson have thrived (to different extents) while bouncing between the rotation and the bullpen. On principle, the move makes sense as Pfaadt’s wide pitch arsenal can keep batters guessing even as his cut fastball and four-seamer play well against his offspeed offerings. Unfortunately, Pfaadt has continued to struggle as he posted a 5.94 ERA and 1.380 WHIP in three starts while posting remarkably similar results as a reliever with a 5.30 ERA and 1.393 WHIP over eight appearances. There’s been quite a bit of inconsistency to his performances too as he’s had a few blowups mixed in with a few good appearances while also struggling to be the innings-eater the team might have hoped he would be. So far, he’s had almost as many appearances where he’s gone more than an inning (5) as he’s gone an inning or less (3) with three straight appearances of essentially an inning or less. Interestingly, he has changed his offerings somewhat as a reliever compared to starting with his four-seamer (27%), curveball (20%), and sinker (19%) leading his usage while as a starter he leaned on his sinker (32%) and cutter (18%) much more. Obviously those changes have not led to improved results and even worse, some of the underlying numbers have deteriorated with his walk rate increasing slightly from 8 to 11% and his hard hit rate elevating from 36 to 44%. Those numbers would be more acceptable for a starter who can more easily navigate traffic, but are a death knell for a reliever.
Bullpen versus Rotation
The obvious question then becomes whether it’s more effective for Pfaadt and the team to have him up in the majors as a long reliever or to keep him stretched out in Reno to potentially replace or support an injured starter elsewhere? Unfortunately, we likely will never get a definitive answer, but if I had to hazard a guess, I suspect that the team will option him back to Reno so he can stay stretched out while also working on the mechanics and mentality of coming into a game from the bullpen rather than as a starter – especially since there was functionally no transition time for him between the moves. It would also have the added benefit of giving him some time to psychologically reset and possibly refine his offerings without the extra pressure of needing to perform every night for a team that has played themselves back into the playoff hunt. Of course, there’s always the possibility that the move could backfire by hurting Pfaadt’s confidence, but I can’t imagine he’s feeling particularly confident at this point and if he can reimagine himself as a long reliever (at least for this season), he could be a great weapon for the team in the stretch run.
