Soderling explained to media after the Tomic match that he's had stomach illness for days. It had zapped him of all power and he gave the match a shot since it wasn't any risk for his life/injury but in the end he was in no state to compete.
Karol Beck also called for a doctor with the same complaints vs Ferrer. Didn't watch that match so don't know more about that. But it was also stomach illness apparently.
Now some sources say that even more players are affected and there is a rumor it could be food poisoning from the players restaurant. Might know more about this in a few days but it certainly explains the "tiredness" of a few players.
I hope they can pinpoint the source. In many sports people avoid public restaurants during major tournaments to not risk anything. Possibly will lead to more players doing their own food shopping and cooking I don't know. But in the end things like this shouldn't happen in a slam tournament.
I noted in the funny pictures thread that Nadal did some cooking of his own. Not so funny anymore as some people seemed to think