In Jacob deGrom’s words, it is “frustrating” to miss a start during a year in which, even if fully healthy, he will take the mound only nine or 10 times. But prudence takes priority, and so the Mets scratched deGrom from his scheduled start Friday in Philadelphia due to a stiff neck.

Testing revealed no structural issues in deGrom’s neck, and he said that he could have pitched if absolutely necessary. Even in a short season, however, the Mets did not want to risk further injury. deGrom intends to throw a bullpen session on Sunday or Monday and then reevaluate. For now, he has avoided the injured list, meaning it’s possible he’ll miss only one start.

“It’s really frustrating,” deGrom said. “I debated on trying to go out there, and I think talking over it, it was, ‘Let’s make this hopefully a one-start thing and not really aggravate something, or feeling this change my arm slot and hurt something else.’ These were all discussions we had. So hopefully it’s a one start thing, but it’s basically day by day right now. I love going out there and pitching and competing. And when you're not able to, it really does frustrate you."

Taking deGrom’s place is right-hander Walker Lockett, who posted an 8.34 ERA over four starts and five relief appearances last season. Lockett has been a member of the Mets’ bullpen the past few days, but he has not pitched; before that, the Mets had been stretching him out as a starter at their alternate training site in Brooklyn, so he has about as much stamina as a regular rotation member.

Still, Lockett is not deGrom, the reigning two-time National League Cy Young Award winner who was 2-0 with a 2.45 ERA in four starts. Aside from his neck, deGrom spent his last start battling what he called a “hot spot” on his right middle finger -- essentially a small blister in formation. But deGrom expressed confidence that he could file it off between starts and have no issue taking the mound against the Phillies, and he said the blister played no role in his decision to skip a start.

Of greater concern is his neck, which, like the back tightness that cost deGrom part of an outing during Summer Camp, is not a significant issue in a vacuum. Had this been a regular season in which deGrom could make more than 30 starts, it would be a mere blip.

“We’re not concerned from a long-term standpoint,” Mets manager Luis Rojas said.

But this is a 60-game season, in which every game -- and every start from the Mets’ best pitcher -- is critical. deGrom attempted to throw between starts, but felt abnormal soreness playing catch after his last outing. He abandoned plans to throw his usual dual bullpen sessions between starts and, although deGrom woke up Friday “feeling good,” the soreness lingered as the morning progressed. On Friday afternoon, the Mets officially made the decision to scratch him.

The hope is that by not pitching Friday, deGrom can miss only one start, potentially returning as soon as Wednesday in Miami. He and the Mets will know more in the coming days.

“If I go out there and try and pitch one inning and then go out there for the second and it really stiffens up, it might put us in a worse situation,” deGrom said. “So I felt like it was beneficial to the team to give them a heads up and say, ‘Hey, I don’t know if this is worth me trying to go out there.’”