I'm not sure what comparing what he did his rookie year to this year proves, but he has been a disappointment. I didn't expect 50 homers again but I don't think it should be unrealistic for a first baseman as big as him to slug at least .525. And yes, he definitely has gained weight. A lot. I was watching the 2005 game where he and Rickie hit their first homers of their careers and it was stunning to me how much bigger he's gotten since then.