Cooks (concussion) has been ruled out for Sunday's contest against the Steelers, Lindsey Thiry of ESPN.com reports.
Cooks will fly with the Rams to Pittsburgh, but he'll spend part of the trip meeting with medical specialists as he looks for further opinion on the fifth diagnosed concussion of his NFL career. The 2014 first-round pick previously met with a specialist while the Rams were on bye in Week 9. The Rams hope Cooks will manage to clear the five-step concussion protocol without missing much time beyond Sunday, but given the tricky nature of head injuries, the possibility of a multi-game absence can't be ruled out. Josh Reynolds will likely serve as the team's No. 3 wide receiver as long as Cooks is unable to go.