The Cool Base alternate jerseys and three minor league stadiums (that apparently couldn't fit on the disc) that 2K had promised would come at release are now available in the Xbox 360 Marketplace. Durham Bulls Athletic Park, Hadlock Field, and Legends Field are included. As previously stated these are free to download.
In an interesting twist the content is currently only available to Gold members. Even though it was intended to be included with the game and is meant to go to everyone it seems that the same restrictions placed on demos has been placed on this free content. Thus Silver members are currently unable to obtain the content that they were promised. Hopefully 2K gets on top of this issue as it was a shame that those without Live would miss out completely and it would be ridiculous that people who are connected but just Silver members would have to wait a week to get it.
Also the first pack of trading cards has gone up. In a pleasant surprise "Card Series 2? is free as well. I don't know if there is a way to see what cards are included in the pack but it's safe to assume that they're related to player movement such as adding a Johan Santana Mets card. I checked on both Santana and Erik Bedard and while Santana's card requirement was the same Bedard's was different with it now asking