According to D-Backs reporter Jody Jackson, right-hander Merrill Kelly is expected to be activated and start for Arizona on Tuesday, but with six starters on the roster, manager Torey Lovullo needed to move someone to the bullpen.
That someone was Brandon Pfaadt.
Pfaadt will move into Tayler Rashi’s place in the bullpen, with Rashi being sent to Triple-A Reno as the corresponding move. While he has been a core piece of the rotation for Arizona over the last three seasons, his recent performances have shifted him to a reliever role.

Sep 12, 2025; Minneapolis, Minnesota, USA; Arizona Diamondbacks starting pitcher Brandon Pfaadt (32) walks to the dugout after being relieved in the fifth inning against the Minnesota Twins at Target Field. Mandatory Credit: Matt Blewett-Imagn Images
The decision to send him to the bullpen showcases the Diamondbacks’ strategy to prioritize flexibility and shorter, high-leverage innings for Pfaadt. It also allows him to further develop his swing-and-miss arsenal without sending him down to Reno.
Monday’s loss against Baltimore is an indication that Arizona needs to bolster its bullpen with proven arms that can limit damage per inning. Pfaadt has shown the capability to do that, with the D-Backs now able to utilize him in different situations.

Arizona Diamondbacks pitcher Brandon Pfaadt (32) throws to the San Francisco Giants in the first inning at Chase Field on Sept. 17, 2025. © Rob Schumacher/The Republic / USA TODAY NETWORK via Imagn Images
Among the five starters this season, Pfaadt has posted the worst ERA (5.94) and the second-worst WHIP (1.38) through 16.2 innings. He has struggled to eliminate the “big” inning, often allowing four or more earned runs in a single frame. However, the right-hander has also proven to generate strikeouts and not rely much on soft contact or flyouts.
With Kelly on his way back and Pfaadt’s new role defined, it provides clarity on where the pitching staff stands. The club is betting that a more targeted use of Pfaadt can deliver more consistent results in the long run.