5-second Google search.
http://astanafans.com/alberto-contador-“my-performance-in-liege-is-unknown”.html
"What do you expect about your performance next Sunday?
"I do not know, is a bit unknown. My aim is to gain experience, because to try to win here requires more experience and know better more the course. I'm uncertain."
"How important is the result for you?
"Of course, I'm always happy when I'm ahead, but these results do not influence at all in my preparation and performance that may have in July. It is the same to be third or finish 30."
Alberto does not always ride to win but that's not a knock against him, it would be insane if he did.
And alternatively racing to win in the Ardennes may cause Alberto to flame out at the Tour. There's no way of knowing until he actually tries it.
So in other words he does what Andy does and picks his spots.