Following a tumultuous free agency, Zac Gallen has returned to the Arizona Diamondbacks. The signing was made official on February 15, with Corbin Burnes being placed on the 60-day injured list to make room. Diamondbacks general manager Mike Hazen spoke about the signing to the media, including Arizona Sports’ Alex Weiner.
“We’re just very thankful he’s still here. He was a major piece to what we’ve done, all the good things that have happened to this organization over the last five to six years.”
With a cold market that was going to significantly weaken the Diamondbacks’ draft pick compensation, bringing him back made more sense. MLB insider Ken Rosenthal reported the lack of acceptable multiyear offers led to Gallen’s decision to return to Arizona.
Gallen will enter his eighth season with the Diamondbacks. Hazen acquired the All-Star right-hander in July 2019 for infielder Jazz Chisholm Jr., a move that looks shrewd in hindsight. In 169 starts, he is 65-49 with a 3.61 ERA over 971 innings.
Gallen became just the third Diamondbacks pitcher to record 1,000 strikeouts with the franchise during the 2025 season. He’ll eclipse 1,000 innings early in the 2026 season, also becoming the third pitcher. His rotation mate for eight seasons, Merrill Kelly, will become the fourth pitcher to achieve both milestones not too long after.
Mike Hazen Believes in a Zac Gallen Rebound
GettyZac Gallen will have a chance to rebuild lost value in 2026, something his GM believes will happen.
Gallen’s 2025 season was a nightmare. Going into the year, it was nearly a given he’d secure a nine-figure contract. All he needed was one more solid season. Instead, he pitched to the worst ERA (4.83) and strikeout rate (21.9%) of his career.
But there was a silver lining in that performance that kept the Diamondbacks interested. Between August 2 and September 20, Gallen made 10 starts and pitched to a 2.82 ERA. Over that stretch, he held opposing hitters to a .197/.249/.350 slash with a 21.1% strikeout rate and a 6.6% walk rate.
The expected metrics, which take into account solely a hitter’s exit velocity and launch angle data, supports this run. Gallen yielded a .222 xBA, .350 xSLG, and a .274 xwOBA.
“I know last year was a tale of two halves,” said Hazen. “I’m confident what happened in the second half of last year will snowball into this season. And we’ll be fortunate when that happens as a team.”
For the Diamondbacks to view themselves as a contender, they’ll need Gallen to revert to his 2022-2023 form. In both seasons, he finished in the top five in National League Cy Young voting.
Hazen didn’t elaborate further on how the rotation would shake out. The Diamondbacks general manager gave his standard non-answer to the question to Snakes Territory co-host Jesse Friedman.
“I will have an answer for you on March 26th … There’s no such thing as having too many.”
Merrill Kelly is already slated to start Opening Day, per manager Torey Lovullo. Gallen is likely assured another rotation spot. Ryne Nelson and Eduardo Rodriguez are likely to get spots as well. Brandon Pfaadt, who signed a $45 million extension last March, should have the inside track to the final spot.
Mike Hazen on Paul Sewald Reunion
GettyPaul Sewald is no longer the lockdown closer who fueled the Diamondbacks playoff run, but his experience and leadership will help their bullpen.
Gallen was the only pitcher on the 2023 pennant-winning squad to return to the Diamondbacks. Right-hander Paul Sewald is also set to return. The former closer was instrumental in their run-up to the World Series. However, he had to take a $1.5 million guarantee after back-to-back subpar seasons.
It’s unclear what type of role Sewald will get in his second stint with the Diamondbacks. Hazen didn’t provide much information on that when speaking to the media, including The Arizona Republic‘s Jose Romero.
“We’re still working on how the back end of our bullpen is going to come together. Paul brings that experience and the ability to stand on the mound in those critical situations, and we know what we’re going to get.”
Hazen is also aware of the events that led to Sewald’s ouster from the closer role in 2024. A truly awful month of July, which included four blown saves and had to be bailed out of another, led to the team going in a different direction.
Sewald spent a year with the Cleveland Guardians and Detroit Tigers before returning to the Diamondbacks. As the elder statesman of the bullpen whose been through everything, he should be able to mentor some of the young arms that Arizona will need to rely upon in 2026.
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