An injured one does. Apparently you weren't watching.
You might want to pay attention better when watching a football game. Or, Maybe it's the "mysteries" of the game that confuse you. You might be confusing the SEC championship game w the CFB Championship game.
Tua was not injured in the Championship game. He was Benched and replaced by The backup.
An even if he had a "boo boo" and had to to miss one play - you don't come out of a championship game if you are an elite QB.
Here is the title of the article written by "Sports Illustrated's" Michael Shapiro after the game.
"Alabama's Tua Tagovoiloa Benched, Replaced by Jalen Hurts in Championship Game Blowout"
The only thing hurt w Tua in that game was his pride.
And He looked awfully fine standing on the sidelines while Benched.
Again, not saying he's good - he's pretty good - not just Elite.
An Elite QB doesn't get Benched in a championship game.