If I had to take a educated guess I would say he is only a weekend rider.. but I do know that he hasn't ridden much this year..

 

My girlfriends '08 JUST did this yesterday morning!! There we are, have the gear on, my bike is idling and hers pulls this crap! I "de-gear" and roll it into the garage and get after it. I got it going and I'm pretty sure it was just oxidation on the neg battery terminal. I pulled the battery, sanded all the connections down to be fresh contacts, and it lit right off. She still has the stock battery, so I questioned whether it had finally taken a dump, but it never hesitated starting for the rest of the day. We did about 100 miles yesterday, stopping and starting quite often.

Good luck!!

 

Loose battery cable is the first thing that came to my mind when reading the OP.

 

Mine did the same thing. IT turned out to be a bad relay. I tested the relay myself and everything appeared fine but it would fail while under a load. I took it down to OReilly and had them test it and it turned out to be bad.

I would suggest taking the relay down to the local Autoparts store and have them test it.