That is stupid, if you start a new season or myGM or even myPlayer, you should start with full non-injuried rosters, after all its a video game. The second you start a myGM or season mode, its not going to be like the real NBA season, so the injuries shouldn't be the same as the real NBA.
It should be like it has always been. Just give an option to have injuries on or off.
If you are playing as the celitcs you should be able to use Rondo, if using the Lakers you should be able to use Kobe.
Where is the fun in a video game not being able to use a star player of your favorite team?