After Season mode is started, you cannot change your lineup. During Season mode, level all players including those at the bottom, as they will eventually be put into play. Season mode uses simulate games separated by half hour intervals. You can make changes to your lineup between games using the "Manage Season" option. Use it to bring in rested players for tired ones. You also have the opportunity to use Energy cards to completely refill the energy meters of your important players. Play as many Quick mode games as possible while a season in progress to earn Energy cards.