Well, if it's a misdiagnosis and a cover-up, that pretty much sucks.
If the Celtics are being coy, I wonder how they plan to capitalize on the mystery and intrigue? Sure, I can see a surprise entrance by Garnett providing a huge emotional lift at some point. But at what point do you bring KG back for maximum surprise and utility? Bring him back too early, and this game of charades and mystery doesn't have much value. Wait too long and they may be in a hole that's too deep for KG to dig them out.
Perhaps KG is making good progress on his recovery, but maybe the team needs to buy him just another week or so to get him back to 90-95% as opposed to 75%. Who knows.
If Boston is being sneaky about all this, I think the optimal time to bring him back would be Game 5 against Orlando (assuming Boston wins games 1 and 2 at home). If Boston loses either game 1 or 2, bring him back for the next game.
I feel ok about discussing these bizarre hypotheticals given the mysteriousness of the situation, the lack of verifiable information, etc. At this point, there's not one person outside of KG's inner circle that can be 100% certain about KG's status for any game of the playoffs - from game 1 tomorrow to game 7 of the Finals (should we make it that far). It's nothing but question marks from beginning to end. It's really weird.