According to Sammi Silber of Washington Hockey Now, Brown had been placed on injured reserve and will be out long term with a lower body injury.
The injury occurred during Monday nights contest against the Vancouver Canucks when Brown was taken into the boards by defender Noah Juulsen early in the third period. Here's the play:
Brown, 28, has no points through 4 games with the Capitals this season. However, by all accounts he seemed to be fitting in nicely with the already injury riddled Washington roster.