You must have Grady Sizemore make the All-Star team with a minimum of fifteen games played during the season. If Sizemore is not on your team, check the the All-Star vote totals. If he is among the top vote getters, simply trade him to your team (make sure "Force Trades" is on) immediately before the All-Star break. If you have played the minimum fifteen games in your season, you will earn the card.