Maria Sharapova has dropped out of the Western & Southern Open because of a stomach virus.

It's the second straight tournament Sharapova has missed because of the illness. She also dropped out of the Rogers Cup in Montreal this week. She announced the decision on her website.

Sharapova was the defending champion in the Cincinnati tournament, which opens this weekend in suburban Mason. She's the second high-ranked player to drop out of the tournament in two days. Rafael Nadal withdrew on Thursday because of lingering problems with his left knee, which also forced him to miss the Olympics and the Rogers Cup.

Sharapova won the silver medal in London, losing to Serena Williams 6-0, 6-1 in the gold medal match. She plans to play in the U.S. Open.