Interestingly, Matthews’s big league success actually began in 2004, and his isolated power has remained steady since that season. It seems possible that he started taking performance-enhancing drugs at the beginning of the ’04 season, but who knows.
Will the Angels be able to use this as a way out of his lousy five-year, $50MM contract? Highly unlikely, in my opinion. HGH wasn’t on the banned substance list until 2005, and Matthews has never tested positive for anything. There probably won’t be any suspension and the Jason Giambi situation indicates that the Angels can’t void his contract based on this information.
Here’s a link at Matthews’s minor league teammates in ’04. Based on the SI.com article, one of them may have been involved as well.