Well, I haven't looked at his splits. But I don't see steady decline. I see his OBP being a career high of .405 in 2010 then the next 2 season right at his career norms. His dingers went down last season, but he had twice as many doubles. And each year he's still having more BB's than K's. He'll be fine. He's in a slump, much like Joey is.
And don't get me wrong, I'm not down on Mes either. His time may very well be now...but the ragging on Hanny is excessive (that's all my point was).