Berkman just had "one" knee injury and he's been ice cold since coming back. I'm not saying he won't get some nice numbers, but he's definately a shell of the man he was last year.
In that same context, yes, Mags has only had an injury influenced season this year, but it doesn't mean he's going to jump back into to his pre-injury form. Also, he's no spring chicken, he's a whopping 31 y/o!
Also, an "injury prone player" has to start somewhere
. I remember Griffey having some great years before someone made a Voodoo doll of him.