Douglas (concussion) wasn't spotted participating in practice Wednesday, Mike Reiss of ESPN.com reports.
Though head coach Bill Belichick was previously unwilling to confirm as much, Andrew Callahan of the Boston Herald relays that Douglas entered the NFL's concussion protocol after being forced out of this past Sunday's loss to the Giants. Given that Douglas was previously diagnosed with a concussion Oct. 8 and proceeded to miss the Patriots' ensuing Week 6 game, the wideout may face an uphill battle to clear the five-step protocol ahead of this Sunday's game against the Chargers. If Douglas is sidelined Week 13, DeVante Parker, JuJu Smith-Schuster and Tyquan Thornton would be in line to lead the team's receiver corps.