CLEVELAND -- The Pittsburgh Steelers fear starting running back Rashard Mendenhall tore the ACL in his right knee during Sunday's 13-9 win over the Cleveland Browns, a source told ESPN NFL Insider Adam Schefter.
Mendenhall was scheduled to undergo an MRI later Sunday to confirm the diagnosis.
"It's not good, of course, when a guy goes down in open grass and is not touched by anyone," coach Mike Tomlin said. "Experience tells me that, in general, that's not good."
After the game, Mendenhall left the stadium on crutches, his head hanging in disappointment. Tomlin said Mendenhall would be examined when the team gets home.
"You should anticipate that he won't be participating next week," Tomlin said, referring next Sunday's wild-card matchup in Denver.
Mendenhall got hurt on a 5-yard carry on the final play of the first quarter against Cleveland. Mendenhall walked slowly to the sideline, where he was checked by Pittsburgh's training staff before heading to the locker room for further tests.
Mendenhall rushed for 38 yards on eight carries before getting hurt, giving him 928 yards this season. He has run for more than 1,000 yards in each of the past two seasons. He also passed Walter Abercrombie for ninth place on the team's career list.
Mendenhall was replaced by Isaac Redman.
Information from ESPN NFL Insider Adam Schefter and The Associated Press was used in this report.