In any sport, retirement only comes into the picture if they reach a certain age where their body can no longer stand the wear and tear. But in football, the case is different. The physicality is entirely different and this best explains why Andrew Luck, 29, decided to announce his shock retirement.

Luck, the first pick of the 2012 NFL Draft who is also a four-time Pro Bowler, made the announcement Saturday night, CNN reported. Injuries are the main reasons behind his abrupt decision, something he admits took away his enjoyment for the game and is preventing him from enjoying a normal life.

"This is not an easy decision," the Indianapolis Colts player told reporters. "For the last four years or so I've been in this cycle of injury, pain, rehab, injury, pain, rehab. And it's been unceasing and unrelenting ... and the only way I see out is to no longer play football."

After the 2016 NFL season, Luck underwent surgery to address a nagging right shoulder injury that lingered since 2015. He would go on to miss the entire 2017 season but made a surprise comeback in 2018. That earned him the NFL Comeback of the Year honor although it remained that he was playing through pain. And from there, the decision to retire came since he could no longer put his heart in the game.

It was shocking news, particularly for the followers of the Indianapolis Colts -- the only team he played for since entering the NFL in 2012. Normally, heroes would be applauded or feted for their years of service. Unfortunately, Luck did not get any of that. Instead, some booed him - something he admitted hurt.

"Yeah, it hurt," he said in a report from the New York Times. "I'll be honest, it hurt."

With Luck's exit, the Colts are expected to turn to Jacoby Brissett. He filled in for Luck in 2017 and threw 3,098 yards that season. Serving more as a backup quarterback, the former New England Patriot will likely get an opportunity to show coach Frank Reich that he can be a starter. The 26-year-old may not be in the level of luck but if he plays his cards right, Brissett may finally get that dream starting job. At some point, pundits feel that Brissett would have tested the market. Now, he may no longer have to, Yardbarker reported.

Andrew Luck Indianapolis Colts
Andrew Luck #12 of the Indianapolis Colts throws a pass in the game against the Jacksonville Jaguars in the fourth quarter at Lucas Oil Stadium on November 11, 2018 in Indianapolis, Indiana. Andy Lyons/Getty Images