DENVER -- The Padres' brutal rotation luck continued on Wednesday afternoon, with their newest starter forced to leave his debut early due to injury.

Right-hander Jake Arrieta, who signed with the club on Monday, grimaced and reached for his left hamstring in apparent discomfort after he'd allowed a home run to Rockies catcher Dom Nuñez in the fourth inning of the Padres’ 7-5 loss to the Rockies at Coors Field. Manager Jayce Tingler and a team trainer emerged from the dugout to check on Arrieta, who was promptly removed with what Tingler would call “a mild left hamstring strain."

“Fortunately this is minor, and I shouldn’t be out very long,” said Arrieta, who allowed five runs on seven hits across 3 1/3 innings, making his Padres debut. 

Arrieta noted that he has dealt with left hamstring trouble in the past but that this particular instance felt less severe. The hamstring “grabbed” when Arrieta landed after throwing his final pitch of the afternoon to Nuñez. Tingler noted that Arrieta’s next start is a question mark. (The Padres would easily be able to skip it with a number of off-days on the horizon.)

Right-handers Chris Paddack (left oblique strain) and Yu Darvish (lower back tightness) are already on the injured list. The club remains hopeful that both will return and make an impact for the stretch run. Meanwhile, lefty Ryan Weathers has struggled immensely in his last five starts. With the situation turning dire at the back of the rotation, the Padres signed Arrieta earlier this week hoping he could fill that void after he had been waived by the Cubs.

“It’s an unfortunate intro to the group,” Arrieta said. “I feel bad for what happened. That’s not the way you want things to start off with your new group of guys.”

Arrieta, whose ERA jumped to 7.13 this season, allowed three runs in the first but had mostly settled in before Nuñez's blast. It was his 64th and final pitch, as the Padres turned the ball over to Nabil Crismatt and a bullpen that has thrown more innings than any other in baseball this season.

“I felt great, more than capable of going upwards of 100 pitches, and that was the mindset,” Arrieta said. “That was the game plan going into the start, especially with the guys in the ‘pen being taxed the way that they have recently. 

“I would’ve loved to give the team at least two more innings. And that’s probably the most frustrating part about it, having the hammy happen when it did.”

Perhaps the positive outlook for this beleaguered group of Padres arms is this: Thursday’s off-day is the first of six off-days over the next 22 days -- which should help give their pitching staff a bit of a respite.