Flacco was taken to the locker room after being hit by Kiko Alonso. Getty

Miami Dolphins linebacker Kiko Alonso was not ejected for his personal foul penalty on Baltimore Ravens quarterback Joe Flacco in the second quarter of the Thursday night game at M&T Bank Stadium, but the NFL offices are expected to issue a fine on the defensive star and some will be calling for a suspension.

Flacco was scrambling for a first down and slid near the Dolphins' 11-yard line before getting hit in the head by the lunging Alonso. The hit was so hard that Flacco's helmet came off. CBS cameras later caught blood dripping from Flacco's ear and sideline reporter Tracy Wolfson confirmed that Flacco would not return to the game.

The 32-year-old quarterback looked dazed as he tried to gather himself. Flacco immediately was taken to the locker room for concussion protocol.

Ravens offensive guard Ryan Jensen quickly went after Alonso after the hit, which prompted Dolphins defensive tackle Ndamukong Suh to retaliate against Jensen, sparking a skirmish between the two teams.

Ravens head coach John Harbaugh was irate on the sideline, challenging Alonso right after the hit. Cameras caught Harbaugh visibly upset well after the play.

Ryan Mallett immediately replaced Flacco. On the drive, Mallett completed a touchdown pass to tight end Benjamin Watson.

The Ravens closed the half with a 20-0 lead.

The NFL said it will not have a comment on Thursday night, according to Wolfson.