Here is an interesting entry from The Disabled List Informer. While most of the article speaks of his injury history, and the details of his most recent procedure, there is also a qoute from Geren about how Chavez has looked in the cage recently.
When asked about how Chavez has been looking in the batting cage, A’s manager Bob Geren said , "Everyone I’ve talked to says he looks incredible, I mean, really, really good. Better than anyone expected."
The Disabled List Informer is written by a physical therapist, and he seems to give the clearest descriptions about players heading to, or coming off the DL. (A handy reference for an A's fan). I read his site a bunch last year.
There is also an entry on The Duke's chance of a repeat perfomance in 2009.