KG and the C's may feel that he has only one game in him -- in other words, they may believe that playing him at all puts him at high risk for aggravating (if not further damaging) the knee (though I assume if they think long-term damage could arise, they would not even consider playing him).
So, if you knew you had only ONE shot to give it a go with KG -- it makes sense to me to wait it out as long as possible -- at least till the ECF. It is unlikely (IMO) that we beat Orlando without KG -- but, if the premise is correct that we can have just one game, then my vote is to let it ride on the shoulders of PP, RR, RA, KP and BBD for this entire series and hope for the best. Then, I'd strongly consider rolling him out for Game 2 in Cleveland (presuming the C's lose Game 1). Beating Cleveland is a huge longshot without KG, but is dependent upon gaining HCA and then holding home court.