is that he was also viewed as a competent backup, though more of a 3rd string QB by the last several years of his career than a second string QB. But he actually started 10 games for Philly in 1996, stepped in for the Niners and got a big win against the Panthers in a start in 1998.

But after one disastrous start for Detroit in 2001 he never really saw the field much. But it isn't hypothetical - several of his former teammates and coaches (I know of Marty Mohrinweg, Steve Mariucci and Steve Young) have commented on his ability to break down the game and his value in the film room.

And the Falcons brought Detmer in specifically to mentor Mike Vick in the West Coast offense: http://articles.philly.com/2004-04-01/sports/25363704_1_rich-mckay-west-coast-offense-quarterbacks-coach