2013 Winston-Salem Open top seed Tomas Berdych has withdrawn from the tournament due to a shoulder injury, and two-time defending Winston-Salem Open champion John Isner also has withdrawn due to a lingering hip injury that flared up last week at the Western & Southern Open in Cincinnati.

Berdych aggravated the injury last week while playing in Cincinnati, where he reached the semifinals.

"We hate to lose one of the top players in the world in Tomas Berdych from our field, but we understand his need to return to full health," said Tournament Director Bill Oakes. "Tomas entertained our fans last year with his run to the final, and we hope to have him back at the Winston-Salem Open in future years."

A finalist at the Winston-Salem Open in 2012, Berdych is currently ranked No. 5 in the world.

After arriving in Winston-Salem, Isner continued to experience discomfort, and after consultation, he decided to withdraw from the Winston-Salem Open in order to give the injury time to heal before next week’s US Open.

"It is really unfortunate I have to withdraw from the Winston-Salem Open, one of my favorite tournaments of the year," said Isner. "I’ve had so much success playing in front of great crowds as well as my friends and family. This was a really tough decision but with injuries taking me out of the Australian Open and Wimbledon, I need to fully heal prior to the US Open."

"We are disappointed for our fans that John has been forced to withdraw from the tournament, but we join him in wanting to make sure he is completely healthy before he takes the court," Oakes said. "He has been a wonderful ambassador for the Winston-Salem Open, and we wish him the best of luck at the upcoming US Open."

Berdych and Isner will be replaced in the Winston-Salem Open draw by lucky losers from qualifying.