The Diamondbacks Are Trapped in a Zac Gallen Nightmare

This has been difficult to watch.

May 23, 2026; Phoenix, Arizona, USA; Arizona Diamondbacks pitcher Zac Gallen (23) throws a pitch against the Colorado Rockies in the third inning at Chase Field. Mandatory Credit: Anna Carrington-Imagn Images | IMAGN IMAGES via Reuters Connect

Every game started by Arizona Diamondbacks right-hander Zac Gallen is beginning to feel the same.

On Wednesday night against the San Francisco Giants, Gallen looked different. He looked confident, sharp and composed. He was mowing down his opposing batters and displaying some of his best fastball command since, arguably the early portion of the 2024 season.

And then, in just 1.1 innings following that hot start, Gallen's excellent outing fell apart, in an all-too-familiar sequence of events.

Zac Gallen shelled after strong start vs Giants

Jun 26, 2026; St. Petersburg, Florida, USA; Arizona Diamondbacks pitcher Zac Gallen (23) pitches during the seventh inning against Tampa Bay Rays at Tropicana Field. Mandatory Credit: Pablo Robles-Imagn Images | IMAGN IMAGES via Reuters Connect

Gallen had allowed only one base hit — a single — through the first four frames. He did not walk a batter, and although he was not racking up swing-and-miss, was living well on weaker contact, including a run of four straight ground ball outs between the first and second inning.

But the fifth inning got away from the right-hander in a hurry. He gave up a solo home run to open the frame, followed that up with a single, then coughed up a second long ball to the exact same area of left-center field.

Suddenly, a scoreless outing was teetering on the edge of a non-Quality Start. The sixth inning would erase those hopes altogether, as Gallen gave up a pair of two-out RBIs. With one out in the sixth, he was pulled for Ryan Thompson, who allowed an inherited runner to score.

So a night that began so spectacularly ended with Gallen being charged for seven base hits and six earned runs in 5.2 innings.

Zac Gallen's struggles are a recurring nightmare for D-backs

Jun 20, 2026; Phoenix, Arizona, USA; Arizona Diamondbacks pitcher Zac Gallen (23) reacts after being taken out of the game in the fifth inning against the Minnesota Twins at Chase Field. Mandatory Credit: Rick Scuteri-Imagn Images | IMAGN IMAGES via Reuters Connect

That six-run outing was the seventh time this season Gallen has allowed five or more runs to cross home plate. It was the 10th time he was unable to complete the sixth inning. Despite some occasional flashes, the ace Gallen once was has not been present.

Following Wednesday's game, his ERA has shot up to 6.36, which is still the worst among qualified major league starters.

Nearly every start, even the ones in which Gallen looks like he has good stuff, has ended in similarly disappointing fashion this season. He's not striking out batters, not collecting swing-and-miss, and hardly offering his team a chance to reasonably win a baseball game.

And yet, the Diamondbacks can't quite afford to part ways with him, yet. With both Michael Soroka and Ryne Nelson down on the IL, Arizona's pitching depth is already being tested. Rookie Jose Cabrera and righty Brandon Pfaadt have already been called up to serve emergency roles.

The D-backs would have to feel comfortable enough to ride with Mitch Bratt, who was optioned after his MLB debut, before pulling the trigger on a DFA. For as poor as he's pitched, Arizona needs Gallen. But it's been difficult to watch.