Maybe he is hiding something like Rafa has apparently being doing for over a year, despite him saying he hasn't.
Not sure if that is directed at me, but if it is Kneedal was off the tour for over 7 months with supposed chronic knee injuries.There has been absolutely no sign of any form of knee problems since he returned. Ergo there has to be another reason for his absence. Kneedal was undoubtedly hiding something.
As for Murray. His performance was so woeful in that match, and so out of character - how often have we seen him rolling over like that in a GS match? He was out for the FO with a back injury, apparently needed painkilling injections or tablets to get through some of his Wimbledon matches, and has been far from his best since.
In exactly the same way as Nadal in such a high energy, power driven sport I would expect chronic injuries to have a lasting impact. It might well be that the back is still not right. He might well have returned too soon, and given his all to get through Wimbledon.
I still think that mental exhaustion is also a big feature of this.
It's interesting that almost without fail, people in the know are totally unsurprised by what has happened, any fully supportive of him.
In WW2, the highest rate of mental breakdowns (certainly for women), was not when the bombs were raining down, and nobody knew one day to the next if they or their loved ones were going to be alive the next day. It was at the end when everything was over and everyone was safe. People can keep going under extreme levels of stress but eventually pay back time arrives. It arrived for Murray two days ago.
Note I am in no way deriding people who have survived wars, by comparing playing a few tennis matches with being bombed. The analogy is about people being exposed to prolonged periods of high levels of stress. In Murray' case he has been carrying the weight of the Wimbledon expectation for all of his adult life.