This was supposed to be the bounce-back year. After the Diamondbacks and Gallen couldn't agree on a long-term extension, he took a one-year prove-it deal worth roughly $22 million to re-up in Arizona and reset his market for next winter. Instead, 2026 has been a slow-motion collapse, and now it's officially catching up to his body.
Zac Gallen Dealing With Elbow Inflammation, Won't Start Sunday t.co/BTDXiSBzyh
The scratch turned out to be the warning shot, not the whole story. A day later came the follow-up nobody wanted: Gallen's rough season takes another bad turn with an actual trip to the injured list, not just a skipped start.
Zac Gallen's rough season takes another bad turn with a stint on the #Diamondbacks' injured list: t.co/nse9eyceVM
The numbers explain why this stint feels less like bad luck and more like a season finally boiling over. Gallen's ERA has climbed into the 6.30s, among the worst marks of any qualified starter in baseball this year, a jarring fall for a guy who was a legitimate Cy Young-caliber arm as recently as 2022-2024. His signature curveball, the pitch that used to miss bats at an elite rate, has been getting hammered, and hitters are teeing off against him at a career-worst clip all season.
None of that erases the fact that Gallen had, until now, been one of the more durable arms on Arizona's staff, never really dealing with a serious arm injury in his career. That track record is part of why an elbow issue popping up now stings extra for a Diamondbacks team that's leaned on him as a rotation anchor for years.
For fantasy managers and prop bettors who've been riding Gallen out of habit or name recognition, this is the final straw on a season that's already been brutal to hold. The Diamondbacks now have to piece together a rotation without their supposed ace while he deals with the elbow, and every start he misses is another data point in what's shaping up to be the worst year of his big-league career.