Rams running back Todd Gurley has arthritis in his knee, Jeff Howe of The Athletic reports.
Gurley's left knee is the same one that underwent an ACL repair in 2014.
Speculation swirled around Gurley's health after the star running back was used sparingly by Los Angeles during the team's 2018 playoff run. Gurley missed the Rams' last two regular-season games but then returned for a solid performance in the divisional round game against Dallas, which was followed by two limited games in both the NFC Championship and Super Bowl LIII.
The 24-year-old was expected to be back in form on Super Bowl Sunday after a disappointing showing in his team's NFC championship overtime win but instead posted another underwhelming performance. Gurley finished with 10 attempts for just 35 yards and one catch for a loss of one yard in the loss.
Gurley told reporters after the game that his knee was fine.
The Rams have not commented on Gurley's reported diagnosis or potential treatments. The young running back's contract guarantees him $34.5 million in 2019 and another $9.5 million still guaranteed for injury.
Gurley finished the season with 1,251 yards on 256 attempts and an additional 580 yards on 59 receptions for 21 total touchdowns. He has been with Los Angeles since the team took him 10th overall in the 2015 NFL draft.