It may never be known what constellation of ills Seau was confronting. He was revered for playing through injuries. And, said former USC coach Pete Carroll, "he wanted to play forever." In fact, Seau's first retirement lasted just four days—he announced he was leaving the game on Aug. 14, 2006, only to sign with the Patriots less than a week later. In 2010 he announced his intention to retire for a second time, saying he planned to "go surf." "A lot of guys say, 'Now I can get back to fishing and golfing and hunting,'" says Ken Ruettgers, a Packers tackle from 1985 to '96 who wrote his 2007 Ph.D. dissertation on the difficulties NFL players have in transitioning from football. "That lasts for about a season, and then they get bored."
Ruettgers now works with recent NFL retirees and suggests an array of interventions, most commonly marriage counseling. "When your life changes like that, so does your relationship," he says. "It's almost like having to get remarried."
Brain-trauma experts who spoke with SI hoped Seau's legacy would not be fear among players about an unstoppable decline into depression but rather renewed efforts to track players and all their complex issues. "Americans are interested in very reductionist explanations, but I would consider the concussion issue the tip of the iceberg" with regard to depression, Schwenk says. "And the iceberg is the reservoir of misery these people have."