Zac Gallen Reportedly Returning to Diamondbacks

The Arizona Diamondbacks are bringing back their former ace.

Sep 20, 2025; Phoenix, Arizona, USA; Arizona Diamondbacks pitcher Zac Gallen (23) pitches against the Philadelphia Phillies during the third inning at Chase Field. Mandatory Credit: Joe Camporeale-Imagn Images | Joe Camporeale-Imagn Images

The Arizona Diamondbacks are closing in on a deal with former ace Zac Gallen, according to recent reports by MLB.com's Steve Gilbert and AZCentral's Nick Piecoro. The deal is pending a physical.

It's a one-year deal for Gallen, who had expected to see a robust market in free agency this offseason after turning down the Qualifying Offer from Arizona.

The deal is for the exact same amount as the QO: $22.025 million, according to insider Jon Heyman. Heyman also reported that Gallen had multi-year offers on the table, but wanted to stay in Arizona.

Per The Athletic's Ken Rosenthal, $14 million of this amount is deferred. Arizona Sports 98.7's John Gambadoro reports that there are no options or incentives present. It is a strict one-year contract.

Diamondbacks On SI will continue to update this article as more details are rolled out.

Arizona Diamondbacks Bringing Back Zac Gallen

Sep 15, 2025; Phoenix, Arizona, USA; Arizona Diamondbacks pitcher Zac Gallen (23) pitches against the San Francisco Giants during the first inning at Chase Field. Mandatory Credit: Joe Camporeale-Imagn Images | Joe Camporeale-Imagn Images

Gallen endured the worst season of his MLB career in 2025, pitching to. 4.83 ERA over 192 innings. Despite that, he had begun to reemerge in the latter end of the year, throwing to a 3.32 ERA following the trade deadline.

The Diamondbacks will hope that Gallen can return to the ace-like form that saw him deliver a 2.54 ERA in 2022, or start the All-Star Game in 2023 on the way to a World Series appearance.

Gallen owns a career 3.58 ERA and 3.65 FIP to back it up over the course of seven major league seasons.

This move comes just a day following GM Mike Hazen's comments that Arizona was still in the market for both starting pitching and position players.

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Though the D-backs' rotation is currently full in theory, excess depth is never a negative, especially as the team awaits the return of ace Corbin Burnes from Tommy John Surgery.

Despite the initial declinining of the Qualifying Offer, Gallen had remained consistent in his messaging: he always preferred to return to Arizona, if possible.

"I think people understand what Phoenix means to me. My wife is from here, I'm calling this home base now. So for us to be here would be awesome," Gallen said in a recent interview.

Manager Torey Lovullo shared the sentiment during his media availability at the beginning of spring training this past week.

"Zac's an incredible pitcher. I don't know exactly what's going on," Lovullo said, while Gallen was still a free agent. "I don't know why he's still out there. But if something happens and he walks back into this clubhouse, we would welcome him with open arms, certainly."