Buffalo Bills running back Karlos Williams is hospitalized, coach Rex Ryan announced Monday.
The rookie tailback "was in a lot of pain" when he woke up Monday, Ryan said.
The extent of the injury is currently unknown.
Williams led the Bills in carries with 14 during Friday night's 25-24 loss to the Carolina Panthers. He earned 40 yards on the ground with one touchdown and added two catches for 23 yards.
Williams has impressed the coaching staff during training camp enough to leap Bryce Brown on the depth chart. Williams is a tough, aggressive, physical runner and possesses good hands in the passing game. With Fred Jackson injured at times last year, the Bills RB3 job could end up having a fantasy impact at some point this season, so it's something to watch.