Apparently some Xbox 360 and PlayStation 3 users have been experiencing an issue where the All-Star Weekend DLC causes auto-sims to the end of the season in MyCAREER and Association. If you're one of those unlucky folks who have been afflicted, please be advised that 2K is aware of the issue and according to Ronnie, a fix is coming in an upcoming patch:
Dev is aware of the issues with simmed seasons post All-Star break for some who have DLC. Will be addressed in future patch
No word on when said patch will be out.