Miami Dolphins running back Raheem Mostert admitted he was surprised to learn Tua Tagovailoa suffered a concussion in Sunday's 26-20 loss to the Green Bay Packers.
Speaking to reporters about the situation, Mostert said he was initially "shocked" when he learned about the diagnosis, but he added it "kind of made sense" after watching how Tagovailoa looked at the end of the game.
Head coach Mike McDaniel confirmed Wednesday that Tagovailoa was diagnosed with a concussion. The third-year quarterback self-reported symptoms Monday and was placed into concussion protocol.
It's unclear when Tagovailoa suffered the injury. He did appear to hit his head on the turf in the second quarter while being tackled to the ground, but he didn't miss any snaps in the game.
Miami had three offensive possessions in the fourth quarter against the Packers that ended with Tagovailoa throwing interceptions.
Tagovailoa is unlikely to play in Sunday's game against the New England Patriots. It would be the third game he's missed this season because of concussions.
He briefly left Miami's Week 3 win over the Buffalo Bills after getting up wobbly when he hit his head on the turf following a hit from linebacker Matt Milano.
It was originally reported by the team that Tagovailoa was being examined for a head injury, but NFL Network's Ian Rapoport said later he tweaked his back early in the game and it locked up after the hit by Milano.
Playing against the Cincinnati Bengals four days later, Tagovailoa suffered a concussion that briefly knocked him unconscious when his head hit the turf on a sack by Josh Tupou.
The NFL and NFL Players Association announced modifications to the concussion protocol on Oct. 8 following an investigation into the procedure that allowed Tagovailoa to go back into the Bills game.
Tagovailoa was held out for Miami's games against the New York Jets and Minnesota Vikings in Weeks 5 and 6. He played in each of the next nine games before reentering concussion protocol Monday.
Dr. Allen Sills, the NFL's chief medical officer, said on NFL Network's Total Access that Tagovailoa displayed no injury behaviors and reported no symptoms that would have triggered him going into the protocol during the game.
Tagovailoa has already set career highs in passing yards (3,548) and passing touchdowns (25).
Teddy Bridgewater is on track to start against the Patriots. The Dolphins can clinch a playoff berth with a win over the Patriots and a New York Jets loss to the Seattle Seahawks in Week 17.
Bridgewater has appeared in four games for the Dolphins this season. The 30-year-old is completing 61.7 percent of his attempts with 522 yards, three touchdowns and three interceptions.