Hernandez is on a roll, but I don't expect a significant breakout. Basically, what you see is what you get, and a slight improvement on last year's numbers is about as much as I'm hoping for.
If you're up for a gamble (and he's catcher-eligible), you might take a look at Matt LeCroy. He has a boatload of power and a good eye for hitting; the only question is how much playing time the Twins will give him.
Also keep an eye on Josh Phelps - if the Blue Jays decide to give him a look, he might be decent (with the usual reservations about putting too much faith in rookies, of course).
And also don't forget about Ben Petrick - he's looking pretty sharp in the minors and might earn himself another chance.
I'm afraid there aren't any sure things at the thin catcher position...