The Dolphins star quarterback -- who battled multiple concussions during the 2022-23 season -- was injured on a run in the third quarter of Miami's "Thursday Night Football" matchup with the Buffalo Bills.

Down 31-10 at Hard Rock Stadium, Tagovailoa was scrambling for a key first down ... when he collided awkwardly with Damar Hamlin -- and appeared to lose consciousness.

Check out footage from the game's broadcast, his body seemed to have a fencing response -- similar to the one he went through during his now-infamous 2022 concussion against the Bengals.

Tagovailoa stayed down for several minutes as trainers raced to his aid. Thankfully, he was able to eventually get up and walk off the field under his own power.

His head coach, Mike McDaniel, gave him a kiss on the forehead as he made his way to the locker room -- and just moments later, the Dolphins ruled him out of the game with a concussion.

It's now at least the fourth time in the last few years Tua's suffered a brain injury -- and on social media, many are wondering if this will put his career in jeopardy.

Notably, ex-NFL superstar Dez Bryant said on X, "That’s it…. NFL go ahead and do the right thing Tua has had entirely way too many concussions He need to retire for his longevity health concerns."