Is Rafa a bit of a scaredy-cat?
As a Rafa fan, I've been trying to figure out what the frequent "will play, won't play" flipflops mean. The silent ban theories don't hold any water IMO because they fail a logic test (why target a conspicuous player like Rafa, why now, why not a monetary fine if ATP is complicit anyway etc)
So it seems to me that the reason for all these flip flops is that Rafa is a bit of a scaredy-cat. I see Rafa as someone who thrives on being the underdog, he loves going into a match thinking that the other player is better and hence he has this 'nothing to lose' attitude. I think this stems from years of Tio Toni telling him that everyone else was better than him and the only way to win was hard work.
I think that's why any time Rafa doesn't feel 100% or doesn't feel like he has had enough practice, he is scared of losing and hence doesn't even want to compete. This stomach virus thing surely shouldn't prevent him from playing at the AO, but maybe its affected his confidence enough that he is scared of being knocked out early at AO.