Does anyone know how to do this? I've looked through all the menu options with no luck. I've done internet searches as well. The only option is for trading players. From what I understand, team rosters cannot be updated if I have created a custom team. (This question is on behalf of my son who plays the game). If the rosters can still be updated regardless of a custom team, then there is nothing to worry about).

What platform?

Other than getting a new roster, you can't.

This was for the Xbox360.

delete the roster, exit out of the game, reload the game and than download the new rosters.