This achievement is easiest with someone like Kevin Durant, Derrick Rose, or LeBron James.
Leave simulation quarters to 12 minutes, as you will be simming to the next key game for this achievement
1. Choose anyone of your liking (I picked Dwight cause he can score and get rebounds, better for the MVP.) Update all his stats to 99
2. Take out anyone over a 80 on your roster. I went as far as taking out every single center over 70
3. Put your player on a team that doesn't have a lot of rivals. I did Charlotte, as their only rival is the hornets
4. Go to rotations, and put your players minutes to 48. Just so he plays almost every minute. Although it may go down throughout the season
5. Start your CAL, simulate, play the key games, and it should be no competition for you, and you get your achievement
(You should edit rosters before starting this mode, for whatever postilion you play trade all players above a 77 to one team on an opposite conference team. Also any superstars should be traded to a team on an opposite conference. This should limit your key games with the Bobcats to 6 or under).