Hickman (concussion) has been ruled out for Sunday's game against the Texans, Daniel Oyefusi of ESPN.com reports.
Hickman entered the league's concussion protocol following the Browns' 23-22 overtime loss to the Saints in Week 9, when he recorded nine tackles (four solo) and two pass defenses. He was unable to practice in any capacity during Week 10 prep, and his absence means rookie second-rounder Emmanuel McNeil-Warren will likely start alongside Grant Delpit at safety, with Daniel Thomas and Donovan McMillon both providing depth at the position. The Browns are on a bye for Week 11, so Hickman will have additional time to progress through the five-step concussion protocol before Week 12 against the Raiders on Sunday, Nov. 29.