Pulling a quarterback from the game, then putting him back in

[dbobo]

Hi, I was wondering if any of you know the rule for this, I recall watching a game a few years back (can't remember the teams) but one team got a big lead of about 20 points and pulled their starting quarterback and put in their second string guy because it looked like an easy win but in the second half the other team made a great comeback, so the other team tried to re-insert their starter and the official wouldnt allow him to come back in because he didnt leave the field of play due to injuries. Is this true that if a quarterback is pulled out of the game, he cannot come back in unless he left due to an injury? Thanks for any feedback.


Drew