michael bishop didnt have the college success or nfl europe success for that matter of davey. hes shown he is capable of leadin a team, hes done so in the past and is a competent backup to tom brady
edit: and of course u didnt adress the fact that if he were thrown into starting they could rely on running this year, he wouldn't have to win games, just not make stupid mistakes and lose them. hes shown(in nfl europe and college) to be a disciplined ball manager
edit: davey's stats in nfl europe last yr
http://www.nfleurope.com/teams/stats/BER
he was 2k1 sugar bowl mvp threw for 3k yards that year. he doesnt SUCK. hes unproven at the nfl level but so was brady when he was thrown into the mix. everywhere he's had a chance davey's been good