The Commanders placed Sims in concussion protocol Wednesday, Nicki Jhabvala of The Washington Post reports.
It's unclear when Sims suffered the injury, but he's had a strong camp and was expected to be Washington's top wideout behind Terry McLaurin, Curtis Samuel and rookie Jahan Dotson. It's unlikely Sims suits up for Saturday's preseason finale against the Ravens, but he'll have more than two weeks to be cleared for Week 1 of the regular season.