“If I’m not here then I’m nowhere,” Mathis said. “Caldwell, definitely, that could be a deciding factor if I decide if I want to play or not.”
Mathis said “Ehh,” if he would play for a coach in Detroit other than Caldwell but that he has not made that decision yet, either. Mathis said "it is tough to elaborate on" what would make the decision for him because of the uncertainty within the organization.
But he said Caldwell is "hands down" the best coach he has played for.
Mathis, 35, said there is not a timetable on his decision. He has one season left on his deal with the Lions.
"It's all my head, meaning how I want to handle things," Mathis said. "Not from a health standpoint, meaning me mentally. I've given a lot and a lot has been given to me and I feel like I have done the best I could with both. And if I walk away, I walk away with my head up. And if I stay, I give it 100 percent again.
"And that's just how I handle things. But the game has been good to me and I feel I have impacted some lives in this locker room and other locker rooms so in that case, I probably beat the game because I've given back. I feel like I've wanted to give back more than I've got so I'm proud of that."
Drafted by Jacksonville in the second round in 2003, he has played in 175 games, making 636 tackles with 32 interceptions, eight forced fumbles and five fumble recoveries. The Lions signed Mathis in 2013 after he was released by Jacksonville following the 2012 season. Mathis turned into a mentor for emerging star corner Darius Slay as well as Nevin Lawson, who replaced him in the starting lineup after he was placed on injured reserve prior to Week 10 with a concussion.
One thing Mathis made clear is that his concussion will not weigh into his decision whether he returns for a 14th season. He suffered the concussion in Week 7 against Minnesota and was not diagnosed with one or placed into the NFL’s protocol until more than a week later.
“I’m healthy with no effects,” Mathis said.
Mathis said he has gone through “every nook and cranny that could have been unfolded or discovered” as he recovered from the concussion. Mathis has been vocal about the NFL, concussions and CTE – including that he will donate his brain to research after death and that he would not let his son play football until high school.
He said he has spoken with his wife, Ebony, about whether he would play next season and that it is a “continuous topic.” Mathis said he needs to spend time with family and then decisions will be made.
Whenever Mathis retires, he said he would like to retire with the Jaguars on a one-day contract, the team he spent the first decade of his career with. He also grew up in the Jacksonville area and makes his offseason home there.
“Jacksonville is home so I think it would be a slap in the face if I did anything other than that,” Mathis told ESPN.com. “I respect my 10 years there and hopefully the people of Jacksonville respect me as well. But Jacksonville was always fun. It was never any bad blood, really, there.
“It’s 10 years there. Ten years weighs a lot.”