Wrist injury knocks 2011 US Open champion out of Flushing Meadows.
The former World No.1 has called it a career at 25.
Former world No. 2 receives wild card into New Haven qualifying.
Meet Riki, a primate prime-time tennis player.
"The only way I can play the US Open this year is if I leave Leo behind in California, which I'm not willing to do," says former No. 1.
Wimbledon semifinalist says small change made major difference in his season.
Former No. 1 opens up about "bottomless hole" after drug ban in interview with Hamptons Magazine.
