Junior Seau’s suicide is troubling NFL players.

No one knows precisely why the 43-year-old Seau shot himself in the chest at his oceanfront home May 2, less than 2½ years after the end of his Pro Bowl career as a linebacker. What is clear — and cause for concern among other players — is that he reached some serious depths of despair.

“To see a guy like that, in such a dark place, to take the action he did … makes you think about life after football … and what you’ll be going through when that time comes, mentally,” said Colts linebacker A.J. Edds, who is entering his second NFL season. “This might have been what people needed to open their eyes a little bit.”

In 40 interviews with The Associated Press during the past two weeks, many players voiced growing worry about the physical and emotional toll that professional football takes. Seau’s suicide resonated among the 13 rookies, 17 active veterans and 10 retirees, with more than half of each group saying it pushed them to consider their future in the sport or the difficulties of adjusting to post-NFL life.

It’s one thing to read about hundreds of guys they’ve never heard of suing the league because of neurological problems traced to a career long ago. It’s quite another to find out about Seau, a charismatic, recent star for the Chargers, Dolphins and Patriots who played in the Super Bowl.

“The difference with Junior for many folks my age or younger is that I played against Junior a bunch. He was a peer. It’s more impactful. Not to suggest I had a great friendship with Junior or knew him off the field. I didn’t. It’s simply closer to home for me than a guy who played in the ’70s or ’80s,” said Pete Kendall, a starting offensive lineman from 1996-2008 for the Seahawks, Cardinals, Jets and Redskins. “All of those kinds of situations are horrible, but Junior’s situation probably would have people re-examining things.”

Indeed it did.

Even less-experienced NFL players in their mid-20s were forced to face some complicated questions in recent weeks.

“You can’t avoid thinking about how the game might be affecting your future. Even something as small as forgetting where I put my keys. I know everyone does that from time to time, but am I forgetful because of football? Have I already done damage to my brain playing the game?” Packers tight end Tom Crabtree, who’s played two seasons in the league, wrote in an email.

“When you see a guy we all assume to be so happy and successful take his own life, it’s disturbing,” Crabtree wrote. “It’s like these brain injuries really turn you into another person. It slowly chops away at your happiness. Nothing you can do about it.”

He was one of a dozen players who, unprompted, mentioned brain disease or concussions in connection with Seau, even though there has been no evidence of either with the linebacker, who played from 1990 to 2009.

Players frequently mentioned that Seau’s suicide prompted heartfelt conversations with spouses or close friends.

“As soon as something like that happens, you start calling all your friends to make sure they’re OK, just checking on everybody,” said Ken Norton Jr., who retired in 2000 after 13 seasons as a linebacker for the Cowboys and 49ers and now coaches that position with the Seahawks. “It just opens your eyes and makes you more aware of what each other is going through.”

In responding to the AP’s questions, rookies were, to a man, certain the league is making things as safe as possible for them. They, of course, have yet to participate in their first training camp or game.

But players who have spent time in the NFL were split on whether they’re properly equipped for what might await down the road. Asked whether the league is doing all it can to take care of players’ financial, mental, physical and neurological health, particularly when it comes to having a good life in retirement, 13 veterans or retirees said yes, while 11 said no.

“There’s a program for everything, but it can’t prepare you for everything. Most people find out about the real world when they’re 18 or 19. Ex-NFL players find out about it at 30 or 35,” said 39-year-old Jon Kitna, a quarterback for the Seahawks, Bengals, Lions and Cowboys from 1997-2011.

“You might think you’ve got it bad in football, because it can be a grind and you might think meetings are a drag, but the real world gives you a totally different mindset,” said Kitna, now teaching algebra and coaching football at the high school he attended in Tacoma, Wash. “There are a lot of programs available, but you have to search for the answers. That’s harder for athletes, because they’ve been given answers their whole life.”

The two men in charge of post-career programs at the NFL and the NFL Players Association readily admit there is room for improvement.

“Do I think enough is being done? A lot is being done. Can we do more? Yes,” said NFL Vice President of Player Engagement Troy Vincent, a former defensive back in the league.

But he also put the onus on players for not participating in what’s available.

“We can continue to expand our offerings, but if the athlete doesn’t engage, it does no good,” Vincent said. “What other employer provides this kind of service for their employee? It doesn’t exist.”

NFLPA Senior Director of Former Player Services Nolan Harrison said the union has been working for years to develop a new “life cycle program” to address various needs during careers in the NFL, from start to finish — and beyond.

Asked if there’s a specific gap that can be improved, the former defensive lineman said: “Every area needs help.”

“They need help with the identity of leaving the game: ‘You’re no longer a football player,’” Harrison said. “They need help understanding they weren’t ever ‘just a football player.’ They were more than that. They weren’t ‘just No. 74.’“