End of a race day
He is tired at the end of a race day. The days start early, and as evidenced by this picture end after dinner. Although each race involves only two runs the racers take advantage of being at a new mountain and ski all day.
There is also a lot of standing around waiting to go, which can be pretty cold, especially in a GS suit!

The picture was blurry because my hand was not quite steady with the long exposure needed to take it in low light. Rather than discarding it, though, I added an effect which blurred it more, which I think somehow adds to the sleeping subject.