article because (albeit 22 years old) it is behind a paywall, but one additional thing he said was how the doctors on the sideline would simply ask how many fingers they were holding up. He said unless you were knocked out, you were going back in.
As I mentioned in another post, when a simulation video was posted the other day on Twitter purporting to show how much the brain sloshes around just by a hit to the forehead with a hand, TB responded that hits like the one depicted happen at least 30-40 times per game for a lineman.