Prosecutors charged the 73-year-old Hewitt, a former member of tennis' Hall of Fame, with raping a girl under the age of 16 in 1981 in Sun City in northern South Africa. Hewitt also was charged with raping another girl under 16 in Boksburg, east of Johannesburg, in 1982.
A third charge of sexual assault of a girl under 18 in Boksburg in 1994 was read out at Boksburg Magistrate's Court.
Hewitt is suffering from anxiety attacks and depression among other health problems, is taking medication and couldn't travel from his home in Addo, on South Africa's southern coast, to attend the hearing, Griebenow told reporters.
A medical certificate from Hewitt's doctor was submitted to explain his absence and later released by the court.
The certificate said that Hewitt's "overall condition had deteriorated rapidly over the last 2-3 years." It described how Hewitt had undergone several operations on his knees and a shoulder in recent years and had also suffered a stroke in 2010 and a heart attack in 2011.
