Well, Mae, usually it's fairly consistent (the scheduling, I mean), the people who play early tend to keep playing early and the people who play later tend to keep playing later. But, I think these guys at this point are pretty much used to anything so aside from the annoyance here or there, I doubt it affects how they play. I mean Robby's played, and done well at, Wimbledon - if you can handle the scheduling there, you can probably handle anything
I still maintain that he did not look sick or weak to me, and not that they know much, but the commentators mentioned nothing too and a lot of the time they will say "well I talked to the player earlier, etc. etc." He didn't look pale or flushed or queasy or whatever - and I've seen plenty of sick players on court before, all the way back to Pete in 1996. He was sluggish but that could be from just the end of the season and the mental and physical grind of what he accomplished catching up to him.
Robby had an amazing season and did better that he had even probably expected to, so I think it's entirely possible that he got to the last tourney of the year and he ran out of gas - mental, physical, both, whatever. I think the same thing happened to Gaudio today in his match - the difference is that he wasn't even trying and it was embarrassing. He was booed, no one felt badly for him, whereas with Robby yesterday, you could just tell that it wasn't his day. No one booed him or anything and the commentators didn't say anything mean like they did today. So he's got almost 2 months to keep up his hard work and rest and he hasn't got many points in the first few months to defend, so he'll be A-OK