Leftwich, the Steelers' No. 2 quarterback, suffered a broken humerus bone in his left arm in the third preseason game last year and was out for the rest of the season, the Pittsburgh Post-Gazette reported.
In 2010, Leftwich was slated to start the first four games while Ben Roethlisberger served his suspension. But Leftwich suffered a sprained medial collateral ligament in his knee and didn't play until the final regular season game against Cleveland.
"This game of football is a humbling game. It teaches you a lot," Leftwich said. "But things happen. Guys get injured in this league all the time. Unfortunately for me, the last few years it's been biting me a little bit. But I got to believe that at some point I'll be healthy, stay healthy and help this team."
Last year, he was scrambling and reached his left arm out to brace himself when he suffered the snapped humerus. If he had broken the bone in his right arm, he said, he doesn't think he could play anymore.
The Steelers plan to have Leftwich be the No. 2 quarterback next season, the Post-Gazette said.