Meriweather collided with teammate Aldrick Robinson during pregame warmups prior to the Redskins' 24-22 win over the Tampa Bay Buccaneers. Robinson was knocked unconscious and suffered a concussion. Meriweather re-injured the knee that had kept him off the field since preseason. He was preparing to make his first appearance of the year, but after the collision both Meriweather and Robinson were placed on the inactive list and were sat out of the victory.
Washington's next game is Sunday at home when they host the Atlanta Falcons. That game kicks off at 1 p.m. ET on Oct. 7 from FedEx Field. Meriweather will miss that game and then be reevaluated in a week's time to see how long the recovery is expected to take, Shanahan said.