Rafael Nadal withdrew from the US Open on Monday due to a right wrist injury.
The World No. 2 and defending champion said, "I am very sorry to announce I won’t be able to play at this year’s US Open. I am sure you understand that it is a very tough moment for me since it is a tournament I love and where I have great memories from fans, the night matches, so many things…
"[There is] not much more I can do right now, other than accept the situation and, as always in my case, work hard in order to be able to compete at the highest level once I am back."
Nadal beat Novak Djokovic 6-2, 3-6, 6-4, 6-1 in last year’s US Open final to add to his 2010 crown (d. Djokovic). He also reached the 2011 title match (l. to Djokovic).
The 28-year-old Spaniard has not played competitively since losing to Nick Kyrgios in the Wimbledon fourth round on 1 July.
http://www.atpworldtour.com/News/Tennis/2014/08/34/US-Open-Nadal-Withdraws.aspx 
Nadal Withdraws From US Open
The World No. 2 and defending champion said, "I am very sorry to announce I won’t be able to play at this year’s US Open. I am sure you understand that it is a very tough moment for me since it is a tournament I love and where I have great memories from fans, the night matches, so many things…
"[There is] not much more I can do right now, other than accept the situation and, as always in my case, work hard in order to be able to compete at the highest level once I am back."
Nadal beat Novak Djokovic 6-2, 3-6, 6-4, 6-1 in last year’s US Open final to add to his 2010 crown (d. Djokovic). He also reached the 2011 title match (l. to Djokovic).
The 28-year-old Spaniard has not played competitively since losing to Nick Kyrgios in the Wimbledon fourth round on 1 July.
http://www.atpworldtour.com/News/Tennis/2014/08/34/US-Open-Nadal-Withdraws.aspx