Indianapolis Colts quarterback Andrew Luck is retiring from the NFL because of mental and physical fatigue, the result of slow recoveries from injuries.

"For the last four years or so I've been in this cycle of injury, pain, rehab, injury, pain, and rehab, and it's been unceasing and unrelenting, both in-season and offseason," he told reporters after the Colts' preseason game versus the Chicago Bears on Saturday. "I felt stuck in it, and the only way I see out is to no longer play football. It's taken my joy of this game away."

An emotional Luck revealed he contemplated retirement for two weeks. He spent the last several months dealing with a calf injury that eventually led to an ankle issue, but the Colts had been optimistic Luck would be ready for the regular season.

"I'm in pain," he said. "Still in pain."

"A week and a half, two weeks...The lack of progress on my ankle. I'm in pain, I'm still in pain."



-Andrew Luck on his decision to retire from the NFL. pic.twitter.com/xuN7FGE7Jv — CBS Sports HQ (@CBSSportsHQ) August 25, 2019

The 29-year-old informed Colts owner Jim Irsay of his decision before the team took on the Bears, according to ESPN's Adam Schefter. He was standing on the sideline with his teammates when the news leaked. A stunned fan base booed him as he exited the field after the game.

"I'll be honest, it hurt," he said of the reaction.

Luck was the NFL's Comeback Player of the Year in 2018. He missed the 2017 season because of a shoulder injury, but then returned to Pro Bowl form last year while leading Indianapolis to the playoffs.

"I haven't been able to live the life I want to live," he said. "It's taken the joy out of this game. ... The only way forward for me is to remove myself from football and this cycle that I've been in."

In 86 career games, Luck threw for 23,671 yards with 171 touchdowns and 83 interceptions. The Stanford product was hailed coming out of college as one of the greatest quarterback prospects since John Elway. He was drafted first overall in 2012 and made four Pro Bowls in six years.

"I know I am unable to pour my heart and soul into this position," he said. "And it's sad, but I also have a lot of clarity in this."

Luck's stunning retirement leaves Jacoby Brissett as the Colts' top quarterback entering the season.