CINCINNATI — The Cincinnati Bengals have signed quarterback J.T. O'Sullivan to back up injured quarterback Carson Palmer.

The Bengals didn't release terms of the contract Friday. They are counting on Palmer's return from an elbow injury last season, but needed a backup after Ryan Fitzpatrick left for Buffalo as a free agent.

The 29-year-old O'Sullivan started the first eight games for San Francisco last season. He also spent time with New Orleans, where he was picked in the sixth round of the 2002 draft.

O'Sullivan has played 14 career games, completing 57.3 percent of his passes for 1,826 yards and nine touchdowns. He also has 13 interceptions.