Tight end is the thinnest position on the Ravens. No tight end on the roster other than Dennis Pitta has played in a regular-season game.
Daniels, 31, would fit with the Ravens because he has familiarity with Gary Kubiak's offensive system from his days in Houston. Durability is the biggest concern. Last season, Daniels played only five games because of a fractured fibula.
"We just have to see how it plays out," Harbaugh said. "It's got to be a fit for everybody. There's a lot to it financially and other things. He's in our conversation."
Harbaugh also mentioned that the Ravens are considering re-signing Ed Dickson to fill the No. 2 tight end role.
There has been speculation that the Ravens could bring in another former Texans player. But right tackle Eric Winston is currently not on the team's radar.
"That's not to say it couldn't change, but that's not a guy we're talking to right now," Harbaugh said.