[IYoDa]

Omg don't listen to these guys.
Start up ps3
Go to add user, DO NOT LOG IN AS YOUR OLD ACCOUNT
Create a new user
Start nba 2k13

This way you have your old user for the MyCareer, Association, All Star DLC etc etc and you now use a SEPERATE user for your MyTeam.

If you delete ANYTHING you will lose EVERYTHING.

Just make another user account on your ps3.