Pittsburgh Steelers linebacker Ryan Shazier has announced his retirement at the age of 28 following an absence of just under three years due to a spinal injury.
Shazier suffered a spinal contusion in a head-on tackle against the Cincinnati Bengals in December 2017, an injury that required surgery to secure and repair the spine.
The two-time Pro Bowler was given a 20 per cent chance of ever walking again, but rehabilitation had him on his feet by the following April when he announced Terrell Edmunds as the 28th pick in the NFL Draft.
Shazier was placed on the reserve/PUP list for the 2018 and 2019 seasons and, although he had spoken of a desire to return to the field, the Steelers moved the player to their reserve/retired list in March.
Shazier confirmed he is now retired on Wednesday in an emotional video posted to his official social media accounts.
Appearing to fight back the tears, Shazier said: "I am here today to make sure the world knows how much I still love football, how grateful I am for everything football gave me.
"I am here today to let the world know that today I am officially retiring from the game I love so much.
"It's been over 1,000 days since I first got hurt. To lose the game in a way I never envisioned has not been easy. When you play the game of football the way I did, you convince yourself you are Superman, that nothing can stop you.
"Then, the moment I got hurt, I stopped being Superman and that was difficult to make sense.
"The way I look at it, God put us all here for a purpose. For 20 years, he let me play football, and now it's time for me to do what he wants me to do.
"I am going to step away from the game for a while and see what else life has to offer. I know football will always be here for me if I need it, but right now I am excited to explore some new challenges and different paths."
Shazier, a 15th overall pick out of Ohio State in 2014, ends his career with seven interceptions, seven forced fumbles, seven sacks and 299 tackles in 46 games.
Ohio State thanked Shazier for "everything" on their official Twitter account, while Steelers colleague TJ Watt paid tribute to a "remarkable team-mate and even better person".