FLORHAM PARK, N.J. -- Shortly after passing his physical and signing a one-year contract Saturday with the New York Jets, Ryan Kalil issued a mea culpa.

"I want to apologize to anybody publicly or behind closed doors that I criticized for retiring and then coming back," he said with a smile. "I totally understand it now. I totally get it."

Kalil, who retired after 12 seasons with the Carolina Panthers, pulled a Brett Favre, saying he missed football and decided to make a comeback when the Jets reached out before training camp.

"I had a hard time moving on, I had a hard time turning the page," the five-time Pro Bowl center said. "I think most players go through this, but especially coming off 2018. [I was] healthy, feeling great, feeling spry. I just felt like I had more football in me."

Kalil, 34, didn't feel that way before the 2018 season, when he was coming off an injury-plagued year and declared 2018 would be his final season. After his final game last season, he returned to his home in Southern California and "started living the beach life."

By March, he had the football itch and started lifting weights. By late May, he was running at 6 a.m. at his alma mater, USC.

The Jets were in the market for an experienced center, in part to help continue Sam Darnold's development at quarterback. General manager Joe Douglas, in his first significant player acquisition, convinced Kalil the Jets were the right team for him.

"It was a unique opportunity with an unbelievable person and player," Douglas said. "I can't tell you how excited I am that he chose to be here."

On Thursday, Kalil agreed to an $8.4 million contract, including incentives. Now the question is, how long will it take him to get in football shape? The Jets are planning to slow-play it, giving him ample time to get ready for the regular season. Coach Adam Gase said they still haven't mapped out a specific plan.

"I feel like I'm in great shape," said Kalil, whose weight is back up to 297 after dropping as low as 260 during the offseason. "Football shape, I'm going to need a little time for that."

In the meantime, incumbent Jonotthan Harrison will continue as the center.

Kalil didn't make an impulsive decision to return. He talked to several former teammates, including Jake Delhomme, Greg Olsen, Christian McCaffrey and Luke Kuechly, and Panthers coach Ron Rivera.

"I'm sure people are mad at me in Carolina and rightfully so, but I love that place," said Kalil, who was a free agent after the season. Kalil said he considered reaching out to former Jets center Nick Mangold, whom he considers a friend. The retired Mangold last played in 2016, and the Jets have been searching for a reliable center ever since.

"I don't know why, but I feel like I needed his blessing," Kalil said. "But I decided not to call him because there was a one percent chance he was going to Ric Flair me and tell me he didn't approve."

The Jets expect Kalil to galvanize the line and have a positive impact on Darnold, who lost his 2018 mentor -- backup quarterback Josh McCown -- to retirement. "The torch can be passed to Ryan this year as far as continuing his development," Douglas said of Darnold.

Darnold said, "It's another tool in the toolbox, I guess you could say, to help us win football games."

Douglas said Kalil's professionalism and reputation will have a trickle-down effect on every young player. One of those young players -- rookie defensive tackle Quinnen Williams -- approved of the move. As he walked past the interview tent, where Kalil was speaking to reporters, Williams shouted, "The GOAT!"