Here's the latest BA prospects blog where it rates the throwing arms of catchers in its prospects guide (qualifications are they had to play in a full season league, face at least 50 SB attempts and be in a team's top 30 prospects).
Mesoraco ranked 54th (next to last) with a 17.4 CS%.
He also made the comments section of the piece:
Devin Mesoraco: Little went right for the Redsí 2007 first-round pick. The low Class A Midwest League isnít kind to hitters, but scouts who saw Mesoraco came away disappointed in his conditioning. Though he did show some power, his offensive performance with Dayton was fairly pedestrian. He wasnít much better defensively, struggling to throw out runners and committing 15 passed balls in 72 games. Mesoraco also battled through injuries to both of his thumbs, so heíll get a chance to regroup in 2009, but it was not an auspicious debut.
It would seem to me the first question that needs to be answered is whether this kid has a future behind the plate.