Agreed. I'm thinking of Joe Nolan as a comp, but I don't know enough about Fleury's defense. I've heard its good enough. Hopefully it better than Nolan's. I didn't consider him as a sleeper because he seems to be known, but he could be a pretty big riser on the list.
If Fleury has a good first half, I could see Grandal on the block at the deadline. Mesoraco/Fleury might make a pretty good tandem down the road after Hanigan leaves.
I think one possible path might be Mesoraco upgrades from Ramon (a lot), Fleury replaces Hanigan as Hanigan gets pricey. Grandal in a package for an impact guy. Barnhardt is a wild card. I like the future at catcher about as much as any spot other than RF (or 1B if they can keep Votto around).