Miami's Kiko Alonso made a nasty hit on Joe Flacco's head as Flacco was sliding feet first. Flacco left the game under concussion protocol. It got Alonso a 15 yard penalty but no ejection.
The announcers thought Alonso should have been ejected. Probably he will be fined.
ESPN: Joe Flacco suffers concussion after hit by Dolphins LB Kiko Alonso
Replays show it somewhat close, but it seems to me that Alonso had time to avert the hit.