Coach Sean McVay confirmed Friday that Cooks has been placed in the NFL's concussion protocol, Lindsey Thiry of ESPN.com reports.
Cooks played 46 snaps and caught one of three targets for a 29-yard gain while also carrying once for 27 yards before he left Thursday's 30-29 loss to the Seahawks with a head injury. Though Cooks needs to clear all five steps of the protocol before his availability for the Week 6 matchup with the 49ers is confirmed, McVay noted that the wideout has thus far been asymptomatic. A follow-up note on Cooks' condition should come next Wednesday, when the Rams resume practicing.