Experience doesn’t make a quarterback immune to injury.

The 10 ACC teams returning starting QBs would be wise to keep that fact in mind. Even though the 10 QBs threw 91.5% of their teams’ passes last season, a backup QB is always one hit or one awkward step away from playing.

Here’s a look at the backup situation at each of the ACC schools.

In good shape:

Virginia returns Michael Rocco (96.5% of Virginia’s passes in 2011), but he’s in a battle for the starting job with Alabama transfer Phillip Sims, one of the top-rated high school QBs in 2009. Sophomore David Watford played in 10 games last season and is easily the best third-QB in the league.

When Florida State’s EJ Manuel (81.2%) suffered a shoulder injury in the Oklahoma game last season, Clint Trickett stepped in for him and threw for 336 yards and three TDs against Clemson.

Duke's Sean Renfree (88.0%) frequently comes out of games in the middle of drives to let his backups, Anthony Boone and Brandon Connette run special packages. While fans and media members are still trying to figure out the method to coach David Cutcliffe’s offensive madness, Cutcliffe promises that things will get even trickier. He may have multiple QBs on the field at the same time for certain plays this year.

Experienced but untested:

Georgia Tech’s Tevin Washington (89.8%) is looking to hand-off first, run second, and then pass in coach Paul Johnson’s offense. Sophomore Synjyn Days has only thrown 12 passes, but he’s also rushed it 48 times.

Clemson’s Tajh Boyd (95.0%) is backed up by Cole Stoudt had 71 snaps in six games. He got into the ACC Championship game and ran a series at the end of the Orange Bowl.

With the rebuilt offensive line in front of Wake Forest's Tanner Price (92.3%), the backup job is crucial. Brendan Cross has appeared in five games over two seasons. Sophomore Patrick Thompson got a handful of snaps in one game. Everyone else is a freshman.

Little or no experience:

Boston College's Chase Rettig (97.8%) is backed up by sophomore Josh Bordner, who appeared in four games and threw two passes.

Virginia Tech's Logan Thomas (96.5%) has sophomore Mark Leal behind him. Leal saw 36 snaps in three games.

North Carolina's Bryn Renner (94.3%) has three freshmen behind him. Double-threat Marquise Williams is the second-teamer.        

NC State’s Mike Glennon (97.2%) saw his backup, Tyler Brosius, transfer at the start of pre-season practice. True freshman Manny Stocker is next on the depth chart.

New starter and backup:

Maryland junior C.J. Brown (38.2%) is backed up by two freshmen: Perry Hills and Caleb Rowe.

Miami’s Stephen Morris (7.7%) is backed up by Ryan Williams, who sat out last season after transferring from Memphis, where he threw 290 passes in 2010, making him the ACC’s most experienced backup.

For more up-to-the-minute news and analysis from ACC bloggers Shawn Krest and Sean Bielawski, follow @CBSSportsACC.