Source -- Pittsburgh Steelers believe T.J. Watt suffered torn pec as he, Najee Harris leave OT win against Cincinnati Bengals with injuries

The Pittsburgh Steelers believe star pass-rusher and reigning NFL Defensive Player of the Year T.J. Watt suffered a torn pectoral during Sunday's 23-20 overtime win against the Bengals in Cincinnati, a source told ESPN's Adam Schefter.

Watt is scheduled to undergo scans Monday to confirm diagnosis, the source said.

Both Watt and running back Najee Harris (foot) exited with injuries in the fourth quarter and were ruled out.

Harris suffered a foot injury as the Steelers attempted to run out the clock, and he limped off the field. Harris was dealing with a Lisfranc sprain in his foot during training camp, but he said earlier this week he was healthy.

Watt came off the field a couple of plays later and went straight to the locker room after sustaining the pectoral injury.