Eerily similar to KG in 2009
Eh . . . not really, no.
KG tried coming back for a game and then went back out again, yes. But he didn't look good at all in that short stretch of play, and he went back out again because of the same injury that put him out in the first place.
In this case, Shaq went out with one injury, finally came back from that one, and then got a different, unrelated, much less severe injury. He also looked great in the short time that he played.
The Celtics have also been fairly upfront with the nature of Shaq's injuries.