Zac Gallen Reunion Creates Major Dilemma for Diamondbacks

Arizona's reunion with their former ace could be a difficult one to fit in.

Arizona Diamondbacks pitcher Zac Gallen (23) prepares to face the Texas Rangers in the first inning at Chase Field on Sept. 3, 2025. | Rob Schumacher/The Republic / USA TODAY NETWORK via Imagn Images

On Friday night, reports surfaced that the Arizona Diamondbacks were reuniting with right-hander Zac Gallen on a one-year, $22.025 million deal, without any incentives or options. $14 million of the deal is deferred.

Per multiple reports, Gallen had multi-year options available to him, but chose to return to Arizona on the one-year contract instead. This is consistent with Gallen's previously-stated desire to stay in Phoenix if possible.

But the reunion does bring a bit of a dilemma onto the table: who is going to be pushed out of the Diamondbacks' rotation?

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Who's Getting Pushed Out of Diamondbacks Rotation?

Jul 23, 2025; Washington, District of Columbia, USA; Washington Nationals starting pitcher Michael Soroka (34) throws to the Cincinnati Reds during the first inning at Nationals Park. Mandatory Credit: Brad Mills-Imagn Images | Brad Mills-Imagn Images

Prior to returning Gallen, the Diamondbacks had five starting pitchers on the major league roster: Merill Kelly, Ryne Nelson, Brandon Pfaadt, Eduardo Rodriguez and Michael Soroka. Corbin Burnes is on the IL rehabbing from Tommy John Surgery, and is aiming for a July return.

Even before Burnes makes his return, the D-backs will need to clear at least one spot in the rotation. The obvious answer is Soroka, who made the transition from starter to reliever in 2025 — and performed well in a limited relief role. But when Soroka was signed, GM Mike Hazen was quite clear they intended to use him as a starter.

Perhaps that was before they knew a reunion with Gallen was on the table. Regardless, there will need to be more than one spot cleared at some point in the season.

One thing is certain: Arizona should avoid moving Nelson, barring a severe down season to open the year. Nelson was forced out of the D-backs' rotation when Burnes initially signed in 2025, struggled as a reliever, then endured a difficult ramp-up back to starting once Burnes went down.

Despite the limitations and pitch count, Nelson emerged as Arizona's best starter. It would be unwise to limit him to a bullpen role again barring a significant drop in his production.

With that said, it will likely be between Rodriguez and Pfaadt for the second clearing. Rodriguez will make $21 million in 2026, while Pfaadt will begin year one of his five-year, $45 million extension with just $3.4 million on the payroll.

In theory, a rotation consisting of Burnes, Gallen, Kelly and Nelson in its top four could be a deadly group. If Pfaadt or Rodriguez are able to have a bounce-back year, the rotation may end up looking like what many imagined it would ahead of the brutal 2025 season.

The signing will also make the opening day starter decision a bit more interesting. Manager Torey Lovullo values seniority, and Gallen was named the opening day starter in 2025 despite Burnes holding a better resume (and larger paycheck).

Lovullo had hinted at Kelly taking on that honor this season prior to the Gallen signing. It may be another lengthy deliberation period for Arizona's manager this spring.