In the first five years of his NFL career, C.J. Mosley missed three games with the Ravens.

Sunday will be the seventh game he has missed this year in his first season with the Jets.

“It’s different, I’ll say that,” the inside linebacker told The Post on Friday. “There’s nothing I can really do to get back on the field. It’s something I just have to let it heal.”

Mosley signed a five-year, $85 million deal with the Jets in March that included $51 million guaranteed. They signed him to run their defense, and for three quarters of the first game it could not have gone better. He returned an interception for a touchdown, recovered a fumble and was all over the field against the Bills in Week 1. Then, he injured his groin while breaking up a pass in the end zone.

The Jets were leading 16-0 at the time. They have not been the same since.

Mosley tried to play last month against the Patriots but looked like a shell of himself. He revealed the injury is not just a groin strain but a core muscle injury.

“It started in the groin and it worked its way up to my lower abs, which sucked,” Mosley said. “I tried my best to finish the [Patriots] game, but I was literally playing on one leg.”

Mosley went to see a specialist two weeks ago, who said he may need surgery. He elected to have platelet-rich plasma (PRP) therapy instead.

“[Surgery] was talked about. I did the PRP shot,” Mosley said. “The recovery time for both was like the same, so I just wanted to avoid surgery if I can. Worst-case scenario is I just do all the rehab and if it’s still bothering me I’ll get the surgery later.”

Mosley said he is taking the rehab slow.

“It’s a 6-8 week process. I’m still in phase one right now, which is balancing,” he said. “I just started walking as part of my rehab. It’s a slow process. You have to take it day by day.”

Mosley did not sound optimistic about returning this season, but said if he can play even one game, he will.

“I’m doing what I can. There’s no need to rush it and make it even worse,” he said. “If I’m not 100 percent, I won’t try to play. If I am, I definitely will try to. I’ve missed the whole season. If I can get at least one game in, I’m going to try. That’s another six months off. It’s going to be a process. It’s all about the longevity.”

The Jets have been ravaged at inside linebacker this season. They are currently starting their sixth and seventh linebackers — James Burgess and Brandon Copeland, who is normally an outside linebacker. Mosley said he has stayed engaged and is treating this like he’s a coach who can help out his teammates.

“You just have to do your best to stay in the loop with the team,” Mosley said. “I’m still going to meetings and taking notes like I’m about to play. That’s my mindset, make sure I stay sharp in my game. I still have a bunch of linebackers in my room that look up to me. I can answer questions for them.”

For more on the Jets, listen to the latest episode of the “Gang’s All Here” podcast: