San Francisco 49ers quarterback Brock Purdy is in the concussion protocol and his status for Sunday's game against the Cincinnati Bengals is uncertain. Purdy started experiencing symptoms on Monday night after the Niners' loss to the Vikings. He is feeling better and will participate in some aspects of Wednesday's walkthrough, but it remains to be seen if he will clear concussion protocol in time to start on Sunday. Backup quarterback Sam Darnold will take reps with the first-team offense on Wednesday.