An MRI exam intended to show that Andy Pettitte’s injured groin was healing instead saved the left-hander from hurting himself more seriously.

Pettitte was checked out Tuesday after feeling discomfort while throwing.

“So that was the whole point in getting the MRI,” Pettitte said Wednesday, “and it’s a good thing we got an MRI because he told me I was going to hurt myself if I tried to push through it.”

The exam showed the strain was still there, and he’s still weeks away from returning to the Yankees.

“It’s just not allowing me to push when I want to go real, real hard. And I’m getting some irritation in there,” Pettitte said. “When I try to push real hard, I don’t know if it’s pain. It tells me don’t do that. When I push hard, it does not feel good.”

The 38-year-old is allowed to play catch and ride an exercise bike, but that’s about it. He can’t throw off a mound for at least a week.

Pettitte’s been told to keep off his feet and is looking at a mid-September return at the earliest.

“To say I’m frustrated, that’s an understatement,” Pettitte said. “I was riding here with my kids and I said, ‘Hey, help me stay positive here.’ I’m already worried about what am I going to do, but I can’t worry about it.”

Pettitte presumably would need multiple bullpen sessions before he could begin a rehab assignment. Joe Girardi said he expects Pettitte might need two rehab outings, so that puts him at around a Sept. 15 return.

That’s assuming he has no further setbacks.

“I literally thought that I was going to be ready to pitch against Boston maybe [earlier this month] or in Kansas City on the weekend, no doubt about it,” Pettitte said. “And obviously that was last week. Now I’m sitting here and I’m not going to be able to get back on a mound for another week. So you’re talking five weeks [that I’ve been] out.”

With Brian Costello