Kim Clijsters Out of U.S. Open

Two-time defending U.S. Open champion Kim Clijsters of Belgium will not go for three in a row this year because of a stomach muscle injury.

Clijsters, who missed Wimbledon with an ankle injury, pulled out of the WTA tournament in Toronto this month with a muscle strain on the left side of her stomach. In a statement Friday, she said "two weeks of rehab is not enough to heal this injury."

"Obviously I'm very disappointed," she said. "I trained very hard this summer and felt in a good shape to play the U.S. Open."

Clijsters, who is now expected to drop from her ranking of No. 3 in the world, said she would also pull out of tournaments in Japan and China in September.