From the Ravens team site,
Harbaugh told reporters yesterday that the team is in discussions with a couple veteran quarterbacks, and that one or some have worked with Offensive Coordinator Gary Kubiak.
The Baltimore Sun’s Jeff Zrebiec said that the Texans current quarterback situation is one to watch,
“Ravens could draft a QB in mid to late rounds. But – and these are my words – probably worth keeping eye on Texans QBsituation. Texans already have three QBs on roster (Fitzpatrick, Yates, Keenum) and are likely to draft one. Could lead to one of their QBs getting released.”
This should come as little surprise especially with Gary Kubiak now in Baltimore running the offense. Adding a backup that knows the system is usually protocol for teams installing new offenses, and the Texans have two quarterbacks in T.J. Yates and Case Keenum who know the system.
Even though Harbaugh has said they are in discussions with current free agent quarterback that know the Kubiak system, quarterbacks like Yates and Keenum could become viable options if released at any point.
This is a Ravens team that needs a backup quarterback for the upcoming season, and signs are pointing to any quarterback that has worked with Kubiak. A trade is highly unlikely but nothing is out of the question in the NFL.