Nick Martin Injury: Enters concussion protocol

Martin has entered the league's concussion protocol and has been ruled out for the rest of Sunday's game against the Browns, Cam Inman of The San Jose Mercury News reports.

The 49ers are on a bye in Week 14, so Martin will have additional time to progress through and clear the league's concussion protocol before San Francisco's Week 15 clash against Tennessee on Sunday, Dec. 14. The rookie third-rounder has contributed mostly on special teams, but his absence further depletes a 49ers linebacker corps that is without Tatum Bethune (ankle) and Fred Warner (ankle - IR).