Indianapolis Colts player Andrew Luck has announced his retirement from professional American football.

The 29-year-old quarterback was the No 1 pick in the 2012 NFL draft as the Colts' successor to Peyton Manning.

He has suffered many injuries in recent years and has struggled to recover from a lower left leg injury.

"This is not an easy decision," he said. "It's the hardest decision of my life.

"But it is the right decision for me."

Word about Luck's plans emerged during the fourth quarter of the Colts' 27-17 pre-season loss to the Chicago Bears on Saturday night when ESPN's Adam Schefter said the player felt mentally worn down and had told team owner Jim Irsay of his decision.

Making it official after the game – in which he did not play – Luck said injuries, pain and continual rehab had taken away his love for football.

In his first three professional seasons, Luck led the Colts to three play-off appearances including AFC South division titles in 2013 and 2014.

He also earned a Pro Bowl selection (voted for by coaches, players and fans) in each of those seasons.

During the 2016 season, Luck injured his throwing shoulder but continued to play.

During the off season he had surgery on the shoulder which forced him to miss the entire 2017 season.

He returned for the 2018 season and was voted to the fourth Pro Bowl of his career and was named the comeback player of the year.

Luck retires with career totals of 23,671 passing yards and 171 touchdowns.

Jacoby Brissett will be the Colts' new starting quarterback.