Clayton, 30, battled numerous injuries that ended his career after seven seasons, finishing with 260 receptions for 3,448 yards and 14 touchdowns. He last played in an NFL game two years ago.
The 2005 Ravens first-round draft pick from Oklahoma announced the retirement on his official Facebook account:
"Time to Retire..
I'm now in the Dungeon working on my new career! NFL as I know it will be something I watch from now on. Ill be retiring this summer and moving on to other things. I'm feeling good and I would like to keep it that way.
I've sacrificed, hurt, bleed, cried, given up and got back up, fought injury after injury and poured all I had into my craft as it pertains to football. The Lord allowed me to go into and grow in some amazing environments. T-Birds of Oklahoma little league, Workman Jr High, Sam Houston High School (Arlington TX), The University or Oklahoma, The Baltimore Ravens Organization, and The St Louis Rams..
I tried my best to give all I had and leave each organization better than when I arrived from attitude to performance..
Big Thank You! To all my family, fans, and Gigantic Support System.. I wouldn't have accomplished what I did without you guys..
Easily the hardest decision I ever made in my life, but right one..
I will continue to lean on you and serve you with my life as I enter into new endeavors.."
Clayton tore his patellar tendon in his right knee two years ago and was placed on the Rams' injured reserve list.
He was traded to the St. Louis Rams in 2010.
In his first game with the Rams, Clayton caught 10 passes for 119 yards. He was placed on injured reserve after the fifth week of the regular season, finishing with 23 receptions for 306 yards and two touchdowns.
Clayton was an All-Big 12 and All-American selection for the Sooners, catching 83 passes for 1,425 yards and 15 touchdowns as a junior.
In his second season in the NFL with the Ravens, he caught 67 passes for 939 yards and five touchdowns.