Victoria Azarenka has pulled out of clay court tournaments in Madrid and Rome with the injury that is threatening to sideline her from the French Open.
The world number four has not played since being beaten in the second round at Indian Wells on March 7 due to a niggling problem in her left foot.
The Madrid Open and Rome Masters take place in the first two weeks of May and Azarenka's withdrawal from them will give her little time to regain fitness before Roland Garros begins on May 25.
"Unfortunately I won't be competing in Madrid and Rome this year," said Azarenka in a video posted on her Twitter account.
The Belarusian, who first suffered the injury while failing to defend her Australian Open title in Melbourne in January, was a beat semi-finalist at the 2013 French Open, which was won by Serena Williams.
