"It's not the depression that kills you," said Jefferson, who was a teammate with the late Junior Seau in San Diego. "It's trying to make that transition to real life without that support group you've had in place your whole career. The depression is a result of not being around your guys any more; that's what kills you.
"The depression comes about because you don't have that structure any more. You aren't walking into that locker room and chatting with your locker mates. You're not in that fire on Sunday with those guys. You are at the door knocking, but nobody will let you in. You don't have that sense of purpose. For guys who retire, there is a dark side to that transition period."
Jefferson speaks from experience. He thought his post-football life would be great. He had saved and invested his money wisely. He had a young family to tend to. He figured he could happily live out his days fishing and, as he put it, "living the salt life."
A year into it, he was struggling. The void, the absence of the game and all of its attending structures, became increasingly unbearable for him.
"I was getting up every day and going fishing," he said. "After a while I was going by myself because my buddies had to work. I would just keep pushing the limits. I would go 50 miles out into the ocean. The next day, I'd say let's go out to where the big boys are and I'd go out 100 miles. But it's not the same. You just can't replace that feeling, that adrenaline rush you get playing the game."
The alienation of the retired player, Jefferson said, is similar to what a soldier feels when he's back from combat.
"People in the outside world don't know what it's like to go into battle with a guy," he said. "Civilians who haven't been to war have no idea what it's like to be in a foxhole with a guy, to depend on that guy to save your life. Basically, that’s what football players do, they depend on each other to save their butts every week. You develop a bond and when you retire, that bond is gone and you crave for it."
Jefferson said he was thrown a lifeline, a lifeline he believes the NFL should finance and promote as much as it does player safety issues. He was asked by former Lions coach Steve Mariucci to take a coaching internship.
"It was by the grace of God that Mooch called me out of the blue," Jefferson said. "I was out of the game a year and he said, 'Hey, what're you doing?' He asked if I was interested in an internship and I jumped at it.
"This was the rope somebody threw me when I was drowning in high water."
He's been the Lions' receivers coach since 2005 and he wishes he could sit down with commissioner Roger Goodell to share some of his ideas. He believes part of the solution is for the league to take measures to keep retired players around the game. He's not saying give them all jobs. He's saying give them access. Establish internships -- coaching, consulting, commentating. Or, more simply, make them feel they are still welcomed, still part of the game.
"You don't know how much good it could've done if Junior Seau could have stayed around the game," Jefferson said. "If he would have come to my practice on a Monday, I would have told him I have a team meeting on Friday and he had 15 minutes to tell the team anything he wanted. He would have felt important. He would have been on that stage again and everybody would have been in tune with him. He would have been thinking about it all week. Can you imagine what that would have done for a guy like that?
"The NFL doesn't get it. They are looking in the wrong places."