Justine Henin-Hardenne is still unsure if she will be able to defend her French Open title.
The world number one returns to training on Monday after three weeks off with a virus infection, but will not compete before Paris.
"We still have to be patient for a few more days to know for sure," a statement on her personal website said.
"The last blood tests came out positive and the doctors gave Justine the green light to resume training."
The 21-year-old Belgian withdrew from the Family Circle Cup in Charleston on 12 April, saying that low blood sugar was causing light-headedness.
She will not defend her German Open title in Berlin, which starts on Monday, or play in any tournaments ahead before Roland Garros.
"After three weeks of rest, Justine will have to find her rhythm fast and she won't be taking any unnecessary risks," her coach Carlos Rodriguez said.
Henin-Hardenne has played in just one clay-court tournament this year, Amelia Island in Florida, where she lost in the semi-finals.
But she has won four titles, including her first Australian Open, a third Grand Slam title in 12 months. Henin-Hardenne still comfortably heads the world rankings ahead of fellow Belgian Kim Clijsters. Clijsters returns to action at the German Open after being sidelined for a month with a wrist problem.
TT Singles: 2014 SF: Bogota, New Braunfels. 2013 F: Las Vegas, SF: Orlando, Sibenik.
TT Doubles: 2014 W: Trnava w PinkTape. 2013 W: St Martin, Orlando, Sibenik, Charlottesville, Nantes-YEC all w Soliloque; Lexington w DJDVD.