Anyway, below is a table that shows estimated framing runs prevented and overall fielding runs above average. The numbers are taken from Baseball Prospectus.
What we see is that the upper minors and majors has no true consistency with respect to how well catchers can frame. Wieters is below average. Joseph and Pena are excellent. Perez, Sisco, and O'Brien are rather poor. I would suggest that due to the difficulty in developing defensively as a catcher that these upper level positions should be saved for players who have already displayed good catching skills or someone who the team is desperately trying to make a catcher (i.e., Sisco).
With that in mind, I compiled a list of minor league free agent catchers to consider for placement in Bowie and Norfolk. The two names that really jump out on this list are Willians Astudillo, a short and stout catcher, and Sebastian Valle. For me, Astudillo seems like the one to aggressively go after. He has shown good contact skills in addition to his defense. He also has shown enough athleticism to play third base. He has no power to speak of, but those bat skills are as promising as free agent minor league catching bats can be. He could be slated for his second tour of AA or given an opportunity to experience AAA.
Sebastian Valle may be 26 years old, but has 10 years of pro ball under his belt. He is your typical minor league catch and throw guy who frames quite well. He would be a solid, no hit option at AA or AAA as a backup. I doubt the bat ever comes around as he has trouble with contact and plate discipline. Tony Sanchez is a former number one pick who has had some offensive and defensive issues. Good plate discipline and framing are his calling cards, but he needs the rest to come together. He probably would look for more of a MLB opportunity. Finally, Kellin Deglan is another guy who was highly regarded, but could never quite put it together. He would be another good option for AA.
It is pretty amazing to think that if you extrapolated playing time for Joseph and Pena in Baltimore, Sisco and Astudillo in Norfolk, and Valle and Deglan in Bowie that the organization would win several more games. Their runs prevented for those three levels would go from -15.8 runs to 54.7 runs, a difference of 70.5. That is worth about eight wins over those three levels. I imagine several pitchers in the organization would appreciate that.