It's not as rare as it once was to see a quarterback start multiple games during his rookie year. Coaches don't get five or six years anymore to prove their worth, so they often turn to rookie quarterbacks to buy more time. A good example of this is in Kansas City where G.M. Carl Peterson and coach Herm Edwards might have saved themselves under the guise of the development of Brodie Croyle.
Sometimes the light comes on after a few years, like for Steve Young who was pretty bad in two years with Tampa and then waited for three years in San Francisco before finally taking the reins. Other players, like Peyton Manning, learn the game by fire -- it costs the team in the short-term (his rookie year, the Colts went 3-13), but it can have tremendous benefits after that.
Here are the most likely rookies quarterbacks to start this year:
1. Joe Flacco: The Ravens are in need of a quarterback, and Troy Smith and Kyle Boller are their only other options. I doubt Flacco will start from day one, but as weeks wear on, and the starters underperform, he'll get his shot.
2. Matt Ryan: as the future of the franchise, Ryan could take over as early as day one. With a depth chart that includes Chris Redman, Joey Harrington, and D.J. Shockley, it's not unimagineable. New coach Mike Smith and new G.M. Thomas Dimitroff will try to do the smart thing, though, and let him learn on the sidelines for as long as possible.
3. John David Booty: The Vikings are a team that believe they're on the verge of the playoffs, and it's true. They are a consistent quarterback away from challenging for the top spot in the NFC North. Incumbent starter Tarvaris Jackson has been marred by injuries and inconsistency, and the pro-ready John David Booty will be lurking in the shadows.