The Metropolitan Police have announced that they will investigate the injury suffered by a Chelsea steward in the Blues' defeat to Manchester United on Sunday.
The match itself was marred by two red cards and an offside decision as United ended Chelsea's unbeaten run in the Premier League this season.
It is not yet clear how the steward suffered the injury, but objects were thrown from the crowd when Javier Hernandez handed the away side the lead in the final 15 minutes.
Meanwhile, the Football Association has opened an investigation into claims that referee Mark Clattenburg used "inappropriate language" towards Chelsea players during the Premier League encounter.