He joins Ryan Mallett and Dustin Vaughan at Ravens camp, which started Thursday. Like Kaepernick, Olson played for Ravens coach John Harbaugh's brother, Jim. The two united at Stanford, before he transferred to Clemson.
Olson passed for 395 yards and nine scores this year for the Kansas City Phantoms. He'll likely serve as a camp-arm as Flacco heals.
On Thursday, Harbaugh said that he has been talking to Kaepernick throughout the summer.
"We had some great conversations on the phone and it's really been a pleasure to talk to him and get to know him," Harbaugh said. "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. It'll all be 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."
Sources told NFL Network that Flacco could be out from 3 to 6 weeks in addition to missing the start of training camp, but the team is not concerned about his availability for Week 1.