The retirement of Colts quarterback Andrew Luck has exposed a divide between players and fans. It’s a schism that may have been hiding in plain sight for years, but Luck’s decision to pack it in 15 days before his team’s regular-season opener shines a floodlight on that disconnect.

Steelers guard David DeCastro, a teammate of Luck’s at Stanford, offered on Monday this assesment of the boos that Luck heard after news of his retirement prematurely leaked, via Gerry Dulac of the Pittsburgh Post-Gazette: “It’s just sad. People treat us like we’re circus animals.”

DeCastro can relate to Luck’s decision to retire after only seven NFL seasons.

“I talked to him the other day,” DeCastro said. “His life . . . it’s been tough. I don’t think people understand how hard it is on the body and mind. When you play the game, you know how hard it is. He did it the right way and was very professional about it.”

Luck’s rollercoaster of injuries began in 2015, when he was limited to seven games. He played through a shoulder injury in 2016, missed all of 2017, and then returned for the full 2018 season, winning the Comeback Player of the Year award.

Plenty of fans believe that paying the price for tickets (and for the stuff that gets sold at a premium at most stadiums) and/or taking the time to watch games on TV gives them a birthright to boo and/or to piss and/or to moan about anything and everything related to NFL players on their favorite teams and/or their fantasy teams, from whether they’re injured to whether they’re retiring to whether they’re performing well enough to whether they care as much about winning and losing as the fans do.

They often cross the line, but the same passion that stirs bad behavior fuels the golden goose. Without true and zealous engagement from fans, the sport doesn’t generate the money that it does. That doesn’t make it right for fans to act like jerks, but it’s not always simple to separate the words that hurt feelings from the deed that line pockets.