He suffered the injury Oct. 27 against Mississippi State when he was sacked.
"I had three ribs come out of place," McCarron told ESPN.com. "They kept popping in and out of place, the one at the top, and it was just a nagging pain the whole time.
"I couldn't throw much during the week for a long time, really almost up to the bowl game. I was hurting really bad through the week, and it just took a long time for those ribs to heal."
McCarron finished the season with 30 touchdown passes, including nine in the last three games. He didn't miss any important snaps as he helped Alabama win the national championship.
"When it first happened, I still tried to throw some so our timing wouldn't fall off that much in our passing game," McCarron told ESPN.com. "That's one of the things that kind of put a damper on our passing game a little. I was injured, and we had so many receivers injured, so it was hard to do a whole lot in practice. That kind of threw us off a little, but we still kept it going."