Federer spending US Open hiking in Swiss Alps

Thanks to a lingering left knee injury, world No. 4 Roger Federer is absent from the US Open for the first time this millennium. On top of missing out on another opportunity to add to his record Grand Slam title haul, he'll lose all 1,200 points he earned for his finals run last year, which will drop his world ranking to at least as low as eighth.

Don't feel too sorry for him, though. In lieu of his annual two weeks in Flushing, Federer has taken to the Swiss Alps for what looks like some pretty incredible hiking.

Let's just hope he's taking it easy on that knee.