The 30-year-old comes over from the Cincinnati Bengals, where he was Andy Dalton's understudy.
Gradkowski becomes the back up for Ben Roethlisberger, who has been somewhat injury-prone over the past couple of seasons. Big Ben only played 13 games last year and hasn't started all 16 games since the 2008 season.
Gradkowski's signing signals the end of Charlie Batch and Byron Leftwich as Roethlisberger's main backups, something that hasn't worked well in recent years. Pittsburgh has struggled when Roethlisberger has succomb to injury, languishing without any semblence of a passing game.
His best season came in his rookie year of 2006 for Tampa Bay, when he threw for nine touchdowns and 1,661 yards. Unfortunately, he also tossed nine picks and fumbled six times, explaining his career backup status.