An injury to quarterback Joe Flacco could open the door for Colin Kaepernick with the Baltimore Ravens.

Ravens head coach John Harbaugh told reporters Thursday he's been in contact with Kaepernick, with NFL Network's Ian Rapoport adding there is interest from the Ravens on the former San Francisco 49ers QB, and the situation depends on what the former San Francisco 49ers quarterback wants.

"I've known Colin through my brother (former 49ers head coach Jim Harbaugh) for many years," Harbaugh told reporters. "We talked and then got to know him very well when he scrimmaged here. He and I have been talking throughout the summer a number of times. We had some great conversations on the phone and it's really been a pleasure to talk to him and get to know him. I like history and politics too, and we've had some debates, and it's been fun. And he's a great guy. He's a guy right now that's being talked about. We'll just see what happens with that. Only speculation right now. He's a really good football player and like I said, I do believe he'll be playing in the National Football League this year."

Kaepernick worked out for the Seattle Seahawks earlier this off-season but wasn't signed by the team.

The 29-year-old QB, who led the 49ers to the Super Bowl during the 2012 season, a game they ultimately lost to Harbaugh's Ravens, made headlines last season when he kneeled for the National Anthem.

Flacco is expected to be out 3-6 weeks with a back injury.