In the six games Shaq has sat, Zydrunas has averaged 8.8 points compared to the 5.0 points he averaged in the first nine games. If O'Neal had to sit six games, the injury was obviously serious. I'd maybe even play Shaq more minutes than Z, but I would have the big man come off the bench to start the game.
One player that has had success lately with Shaq's absence is Jamario Moon. In the nine games Shaq was active, Moon averaged only 3.3 points per game. In the six games Shaq was out, Jamario averaged 7.5 points per game. Moon's minutes are also up significantly.