Colts quarterback Andrew Luck speaks during a news conference following...

Colts quarterback Andrew Luck speaks during a news conference following the team's preseason game against the Bears on Saturday in Indianapolis.  Credit: AP/Michael Conroy

Barry Sanders reacted like most of us when he heard on Saturday that Colts quarterback Andrew Luck had retired at age 29.

“I was shocked and surprised,” the Hall of Fame former Lions running back said on Tuesday at an NFL Network event in Manhattan to promote the league’s 100th season.

But the news resonated more with Sanders than most, because 20 summers ago he made a retirement decision that was even more surprising than Luck’s, in that he still was healthy and productive after 10 years in the league.

“I was as surprised as anyone, but just listening to his press conference it almost took me back a little bit because I understand, yeah, this is a really tough, difficult decision for a young man to make,” Sanders said. “Just trying to pry yourself away from the game is really difficult.

“For me it was something I just kind of grappled with all offseason. It’s a very personal decision, although you play a team game. He must be really banged up and felt he really needed to do this. I know he’ll do well. He’s a bright young man. He’s sharp. He has a lot of great options.

“I can understand how fans were reacting and how insensitive I guess they can be, but [the booing] was just a reaction. Obviously the Colts were very optimistic going into this season that they had a legitimate chance to do great things with Andrew.”

While Sanders has been a popular interview subject in the wake of Luck’s announcement, a closer parallel could be found sitting to Sanders’ left at the NFL Network event in former Broncos back Terrell Davis.

Davis had played seven seasons — only four full ones — when injuries led him to retire in the summer of 2002 at 29, the same age Luck is now.

“I understood 100 percent . . . when he spoke up there at the podium about the toll it took on his body and the mental toll it takes, every day,” Davis said. “People assume that players are indestructible and we don’t have injures and we don’t think like humans.”

Davis made his decision at the last preseason game of 2002. “I walked out of the stadium and told [coach] Mike Shanahan, ‘This is it, I can’t do it anymore.’”

Sitting to Davis’ left was LaDainian Tomlinson, who had better injury luck before he retired in 2011 after nine seasons with the Chargers and two with the Jets, but even he succumbed to the grind down the stretch.

He said in his last year with the Jets, he was counting down the weeks left in his career, knowing the end was near.

“I applaud Andrew because most of us athletes, it’s hard to walk away from something you have done your whole life,” Tomlinson said.

On an earlier panel that featured Kurt Warner, Michael Irvin and Steve Smith, Warner said of Luck, “I think we’re all disappointed. He was one of the great, young stars. But the other side of it I completely understand.”

Warner added, “I tip my hat to him that he didn’t stick around just because he could. He didn’t stick around just so he could make a lot of money.”

To fully understand the toll the game takes on bodies, Warner suggested every fan watch one game from an NFL sideline.

“I remember when I retired and I went and watched a game from the sideline and was like, ‘Gosh, I can’t believe I ever played this game,’” Warner said. “It was so big and so fast.”

Said Smith, “The secret is out: Professional athletes are not robots, they’re human beings. They’re sons, they’re fathers, they’re husbands, and they also want to be able to live the rest of their lives and do the things at 40 years old that they take for granted.”

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