Rafael Nadal pulls out of US Open

(Photo credit: Kirby Lee-USA TODAY Sports)

Four-time U.S. Open champion Rafael Nadal withdrew from the tournament on Wednesday, announcing on social media that he didn't believe he could give full effort later this summer in New York.

The 38-year-old Spaniard, a 22-time major champion, is coming off of playing singles and doubles at the Paris Olympics and failing to add to his two career gold medals.

Nadal said he has "