The Ravens need another quarterback after they began training camp on Thursday without injured quarterback Joe Flacco, who is expected to miss a week with a back injury. Harbaugh indicated Baltimore is primarily looking for someone to help the team only in the short term.
"He's a really good football player," Harbaugh said after practice Thursday. "I believe he's a really good person. It all depends on a lot of things. It depends on Colin first of all and what's his passion, what's his priority, what's he want to do, what kind of shape he's in. So we'll just see where it goes. I don't think it's different for us than any other team."
The Ravens would probably look at Kaepernick if Flacco is out for an extended period.
"We're definitely going to get another arm in here," Harbaugh said.
Kaepernick is more than just an arm or training camp body, though, in Harbaugh's view.
"But he's not an arm, obviously. He's an accomplished football player. You always like having good football players."
Kaepernick has received only one tryout since parting ways with the 49ers, and some say it stems from his kneeling during the national anthem to raise awareness about social injustice.
The Ravens have ties with Kaepernick, who played in San Francisco under Jim Harbaugh. Kaepernick's offensive coordinator with the 49ers was Greg Roman, who is an assistant with the Ravens.
John Harbaugh has talked to Kaepernick a number of times throughout the summer. The conversations have touched on history and politics, and Harbaugh said there have been some fun debates.
"He's a great guy and he's a guy right that's being talked about," Harbaugh said. "We'll just see what happens with that. It would all be speculation right now. I think he's a really good football player, and as I said at the owners' meetings, I do believe he'll be playing in the National Football League this year."
Safety Eric Weddle, one of the team's leaders, said the decision on whether to sign Kaepernick is up to Harbaugh and Ravens general manager Ozzie Newsome.
"I don't care who they bring in or what they do, if it helps our team, bring them all in," Weddle said.
Officials with the Ravens say they won't be without Flacco for too long. Flacco injured his back about a week ago, and it flared up on Wednesday, according to Harbaugh.
"They're recommending a week of rest. They say it should take care of it," Harbaugh said. "I guess with the back, you can always say, 'We'll see.' All indications from back specialist and Dr. [John] Carbone is he should be fine in about a week. That's what we'll be hoping for and praying for."
"I think Joe with a week of rest here is not going to hurt our offense," Harbaugh said. "It might help our offense in terms of developing some of the guys. I would rather go that route than go the other route and push it."
Torrey Smith, Kapernick's former teammate with the San Francisco 49ers and former Raven, feels teams are steering clear of signing Kaepernick because "people are scared of the publicity that comes with it, and Baltimore is a place that can handle that."
"His old O.C. is there as well, and they have a foundation there that can bring anyone in and make them fit to their ways," Smith added. "I'm sure of he gets a shot he'll do fine. I know he's in great shape and he'll be ready to go if he gets that chance. I hope someone gives him a chance."
Smith said Kaepernick has been working out regularly in case a team calls and said critics were thinking his priorities are not right purely by judging from his presence on social media and did not see that "this cat's got his muscle back, he looks his normal size."
"He's working, I do know that," he said. "I know he's going to be ready to go physically, but people only know what he's posting on social media."
ESPN's Tim McManus contributed to this report.