Zac Gallen injury: D-backs ace placed on 15-day IL with hamstring strain, team waiting on MRI results

Already facing an uphill climb in the standings, the Arizona Diamondbacks lost ace Zac Gallen to a hamstring injury Thursday night. Gallen exited his start against the New York Mets at Citi Field with a right hamstring strain after only six pitches and was placed on the 15-day injured list Friday, the team announced. Righty Slade Cecconi was called up in a corresponding move.

“He’s gonna get back to Arizona, get evaluated by our team doctors, get in the tube and get an MRI,” manager Torey Lovullo said about the injury (via KTAR), adding the D-Backs are hopeful Gallen will only miss the minimum 15 days. “Then we’re gonna find out exactly what it looks like and what type of injury occurred.”

Here is the pitch that led to Gallen’s injury. There’s not much to it — he threw a pitch and came up favoring his leg. He didn’t throw a test pitch, instead immediately leaving the game with the trainer. Gallen had a slight limp as he exited the field.

Gallen exited his April 26 start against the Seattle Mariners with tightness in the same hamstring. The D-Backs did not place him on the injured list at the time. Instead, they used scheduled off days to skip Gallen’s next start and give him 10 days off before his next outing. He returned May 7 and had pitched well since, and reported no issues with his hamstring.

“The one in Seattle was a little bit more minor. This one is mild, I guess,” Gallen about his hamstring injury (via MLB.com). “It felt similar to what it did in 2021 (when he missed 15 days with a hamstring strain). I don’t really know the scale. I just knew that I just couldn’t keep going or I would put the team in jeopardy of not giving them a chance to win.”

The D-Backs are already without Eduardo Rodriguez, their big free agent signing, and the reliable Merrill Kelly. Rodriguez has a lat strain, and Kelly has a shoulder issue. Both are on the 60-day injured list and are weeks away from returning. Losing Gallen for any length of time would be a significant blow to a team pushing the limits of its pitching depth.

Arizona’s rotation depth chart looks like this at the moment:

RHP Zac Gallen (out with a hamstring strain)LHP Jordan MontgomeryRHP Merrill Kelly (out with shoulder injury)LHP Eduardo Rodriguez (out with lat injury)RHP Brandon PfaadtRHP Ryne NelsonLHP Blake WalstonRHP Slade CecconiLHP Tommy HenryCecconi, Henry, and Nelson have combined for a 5.93 ERA in 19 starts this season. Even Montgomery, who signed during the final week of spring training, has struggled. He has a 5.48 ERA in eight starts. Walston made his MLB debut earlier this month and held a weak Miami Marlins offense scoreless in 4 2/3 innings in his first start last weekend. 

Even with Corbin Carroll’s season-long slump, the D-Backs are averaging 4.54 runs per game, eighth most in baseball. Keeping runs off the board has been challenge, though. Arizona is allowing 4.65 runs per game, ninth most in baseball. Now they’ve lost Gallen, who has 3.12 ERA and averages close to six innings per start, to a hamstring injury.

The D-Backs are 25-32 this season. They are 5-2 against the very bad Colorado Rockies and 20-30 against everyone else. Arizona is 3.5 games back of the third wild-card spot with five teams ahead of them.