SEATTLE -- Zac Gallen unleashed a 93 mph fastball to Julio Rodríguez in the sixth inning of Friday night's 6-1 loss to the Mariners, and the slugger fouled it off. Gallen hopped slightly after releasing the pitch and it was clear something was not right.

A frustrated Gallen motioned for catcher Gabriel Moreno to come out to the mound and in the Arizona dugout, manager Torey Lovullo feared the worst. And who could blame him after what he’s witnessed over the last month?

It started toward the end of Spring Training when starter Eduardo Rodriguez went down with a lat strain and closer Paul Sewald with an oblique injury.

Once the regular season got underway, the team lost shortstop Geraldo Perdomo and outfielder Alek Thomas to injury. In just the last week, starting pitchers Merrill Kelly and Ryne Nelson had to go on the injured list along with relievers Kyle Nelson and Miguel Castro.

“I can't help myself,” Lovullo said. “Just human nature and everything that we've been going through in the past three or four weeks plus. You can't help but think that it was going to be something more serious. So I intentionally walk out there slowly so I don't have to talk to him. And I just get the word from the trainer and the trainer came back to me and said that it's just right hamstring tightness and it’s kind of spasming on him.”

Gallen, who said he has experienced hamstring issues in 2019, 2021 and 2023, also feared the worst when he first felt the tightness, and if there is something he learned from prior experience it’s not to push through it and make it worse.

After the game, Lovullo and Gallen both were optimistic that it was just a cramp or spasm and that Gallen might not even need to miss a start.

“I didn't feel like it was really too severe, honestly,” Gallen said. “And I feel like I just tried to nip it in the bud before it really got worse and make the smart play and maybe give up an inning or two as opposed to going on the IL for an extended period of time. Only time will tell, but I feel pretty encouraged.”

The first test will be how Gallen feels when he wakes up Saturday morning. He usually does not play catch the day after a start so it will be a day of just getting treatment on his hamstring.

The next test will come Monday when he is scheduled to throw his between-starts bullpen session.

Gallen's optimism that he might avoid missing any time is definitely a positive for the D-backs on an otherwise frustrating evening. After Gallen departed with a runner on first and Arizona trailing 2-1, reliever Scott McGough allowed a single and a walk to load the bases before Mitch Haniger hit a grand slam that hit the top of the wall in left and bounced over.

That made it 6-1 and the D-backs went on to lose for the fifth time in eight games on their current road trip.

“Scott is usually very good at coming in in the middle of an inning and getting us out of some tough spots,” Lovullo said. “It just didn’t happen. I thought we had a chance with the count 1-2 when he entered the game to really go on the offensive and create weak contact with Julio Rodríguez. It didn't happen. And we just got to make better pitches. Scott knows that.”

The D-backs offense squandered several opportunities early in the game, hitting into double plays in the first, second and fourth innings.