Credit EDSBS for being first-to-market with a timely (and satisfying) comparison between the situation faced by Tim Tebow and Florida in 2009 with Tommie Frazier and Nebraska in 1994.
Both were the presumptive favorites to win the national title. Both QBs were considered the best at their position in the country (at the time, we didn't yet know Frazier was an all-time great). Both went to relatively untested backups to fill in some unknown number of weeks.
Brook Berringer and John Brantley aren't a precise match -- Berringer was a year older, running the same system as Frazier. Brantley would run a modified spread, not unlike Meyer used at Utah.
(Meyer and Co. keep talking about the '05 -- even '06 -- offense under the direction of Leak. I see a couple of differences: Brantley has a much better arm and a relatively better running ability than Leak. The Florida RBs in '09 are sick compared to '05. My big question: When will Meyer talk about the player who will serve in the same role for Brantley that Tebow did for Leak: The short-yardage "single-wing" specialist -- Joe Haden? Demps or Rainey? Jordan Reed?)
Anyway: The EDSBS Tebow-Frazier/Brantley-Berringer post is worth your read.