Discussed in early previews for MLB 10: The Show has been the addition of six classic stadiums which not only can be used in exhibition but also in franchise mode. While it was not stated as such in any previews it appears that at least some of them will be paid downloadable content and not included in the game.
The pre-order deal has gone up on the product page for MLB 10 at Gamestop. Those people who reserve it through Gamestop will receive a code to download Shibe Park, Forbes Field, and Polo Grounds.
Obviously there would be no need for a code if the stadiums were available for free in the game or as free downloadable content. This begs the question of whether the other three, those being Crosley Field, Sportsman’s Park, and Griffith Stadium will be included with the game or as downloadable content themselves.
Update: I have been informed that plans for how the stadiums will be dealt with will be provided later this week.