Market asymmetry

Right now the Patriots have two quarterbacks, Matt Cassel and Tom Brady. The former is 26 and has started a handful of NFL games. The latter is 31, rehabbing from a torn MCL & ACL, and has three Super Bowl rings. Who's more valuable?

While you don't know until you try, of course, my bet is that the free market of other NFL teams would pay more for Matt Cassel than for Tom Brady. This is somewhat a function of probably having more teams in the bidding for a Cassel than a Brady. I could be totally off-base on this, and please lemme know if you think so -- especially if you pull for a team that has a crappy QB, whom would you want them to pursue this offseason, Cassel or Brady?