Ryan Kalil figured it was time after the 2017 season.

The All-Pro center was coming off consecutive seasons in which he had dealt with a major injury. He had one year left on his contract. He felt like he was slowing down. Kalil decided 2018 would be his final year in the NFL and he would retire after 12 seasons with the Panthers.

After three months of retirement, though, Kalil began to have regrets. He said he was living “the beach life” in California. He started lifting weights again and he felt the itch.

“I had a hard time moving on,” Kalil said Saturday. “I had a hard time turning the page. I think most players go through this, but especially coming off 2018 healthy, feeling great, feeling spry again. I just felt like I had more football in me.”

The Jets hope he is right. Kalil officially signed with the Jets on Saturday after passing his physical, ending his brief retirement. The 34-year-old believes he can help make the Jets winners and the team’s leadership is confident he will have a major impact on the field and in the locker room.

“When you talk about [the type of] guy that we want in this organization, Ryan Kalil is a guy who checks all those boxes — smart, tough, highly decorated player … as good as he is on the field, he’s an even better teammate,” general manager Joe Douglas said.

Douglas said he first began talking to Kalil’s agent, Tom Condon, just before training camp. Douglas later spoke with Kalil directly and the two hit it off. Kalil said he was sold on Douglas’ vision for the Jets and the two sides began hammering out a contract. They reached agreement Thursday on a one-year, incentive-filled deal.

“He was persuasive because I was still trying to collect my thoughts about the whole thing,” Kalil said. “It wasn’t like, ‘OK, I’m ready to go. Who’s going to call me?’ It was, ‘Maybe I still want to do this.’ When I talked to Joe, we had a long conversation about it. I think he wanted to figure out where my mindset was. We had a few conversations over the course of a few weeks and then it started getting serious.”

Kalil said he reached out to some former coaches and teammates with Carolina, including Ron Rivera, Jake Delhomme and Greg Olsen, to see what they thought. He also checked in with former Jets center Nick Mangold, whom the team has been struggling to replace since 2016.

“I even thought about calling Nick Mangold because I’ve known Nick a long time,” Kalil said. “That was kind of weird. I don’t know why. I felt like I needed his blessing. But I decided not to call him because there was a 1 percent chance he was going to Ric Flair me and tell me that he did not approve. I decided not to call him, but I’ve been talking with Nick for the last week now. He’s been so great. Big shoes to fill around here.”

The Jets are still formulating a plan for Kalil to get ready. They want to ease him in. After losing 30 pounds in retirement, he has regained the weight and weighed in at 297 on Saturday. He said he is in good shape physically, but it will take him a little while to get back into football shape. Kalil has not had pads on since the end of last season.

The Jets believe Kalil can really help second-year quarterback Sam Darnold. The two know each other a little because both went to USC. Douglas remembers how much center Matt Birk helped a young Joe Flacco with the Ravens when Douglas was a scout there.

“I’ve heard how beneficial a guy like Josh [McCown] was to Sam’s development last year,” Douglas said. “I really think that torch can be passed to Ryan this year in terms of continuing that development.”

Kalil said several people told him last year he should keep playing and that was always in his head.

“I’ve been playing football since I was 8 years old, so you can imagine how hard it is to say you’re done and walk away,” Kalil said. “I also want to apologize to anybody publicly or behind closed doors that I criticized for retiring and then coming back. I totally understand it now. I totally get it.”