Has Federer gotten that stomach bug that everybody's been talking about? If so, Raonic has a decent chance here.
He's got something. Seems the stomach is not bugging him, just fever. He says his family is a lot worse off. The health officials in the area are saying it's a 24-48 hour virus, so he may be well enough by Tuesday.
However, just because the virus is gone doesn't mean it's effects are gone (dehydration, fatigue, etc).
However, a Federer/Raonic match was never going to be a festival of 20-shot rallies, so maybe that's the best type of opponent Fed could have in that case.