Joe Flacco has entered concussion protocol, Ian Rapoport of reports (on Twitter). This comes less than 15 minutes after Kiko Alonso delivered a controversial hit to the Ravens quarterback’s head on a Flacco slide attempt. This comes as little surprise to those watching Thursday night’s Dolphins-Ravens game, given the impact of Alonso’s penalized hit, and Ryan Mallett has taken over for Flacco. The Ravens are up 20-0, with Mallett having thrown a touchdown pass after being summoned in the red zone, but the team’s chances obviously take a hit without their starter.