Ronnie2K has already verified that the development team is looking to fix the issue as soon as possible. Until then, stay offline and avoid any online game modes, and you should avoid the issue. Do not delete your save data unless specifically asked to by a member of the 2K team.
UPDATE: Per LD2k, the issue should now be fixed.
UPDATE #2: Seems like the issue isn’t limited to PS3 users, but affects X360 users as well. Per LD2k:
Team monitoring the #NBA2K13 issues. Please continue to provide real-time feedback. Thanks for your patience.
Once again, try staying offline for now.
UPDATE #3: Per LD2k:
We've been informed all the #NBA2K13 should be fixed now. Please log in and tweet back at me.