According to ESPN's Adam Schefter, the 29-year-old athlete has already informed his team about the decision, and is expected to publicly announce his retirement in a Sunday press conference. Schefter reports Jacoby Brissett will become the Colts' new starting QB.
The Colts played against the Chicago Bears tonight and footage from the game showed Luck being booed as he was leaving the arena, a sign that fans heard about the news.
Luck, who was the No. 1 overall in the 2012 draft, has struggled with multiple injuries over the last several years. He was sidelined in 2015 after tests revealed he had suffered a lacerated kidney and a partially torn abdominal muscle. Though Luck also missed the entire 2017 season due to a shoulder injury, he made his return last year, throwing for 4593 yards, 39 touchdowns, and 15 interceptions; however, a recent lower leg injury has prevented Luck from appearing in any preseason games.
You can watch Luck's official announcement, below.