Only one can be playing currently one the field but an unlimited amount of backup qb's can be on the side lines
one at a time *There can be an offensive and defensive QB for each team; four in total.
Only one qb can bev playing on the field, but there may be multiple back up qbs.
1989 as QB started in one game after the original QB was suspended for gambling
Tom Brady!
Drew brees 7
No one
3rd string qb's are considered emergency qb's. If they enter the game before the 4th quarter begins, the starter and his back up can no longer return to the field.
it matters how much possesion your team has
Sid luckman, November 14, 1943
THE BACK UP
The cast of QB Game Analysis - 2009 includes: Josh McCown as himself Mark Robert Ellis as himself
doug williams
Two. One as the starting QB for the Chicago Bears in Super Bowl XX and one as the backup QB for the Green Bay Packers in Super Bowl XXXI.