Serena Williams has pulled out of the Italian Open, a tournament she has won four times.
The move comes just five days after the 23-time Grand Slam champion withdrew from the Madrid Open. She said she needed more time to prepare for her first clay season since giving birth in September.
She returned to the WTA Tour in March and reached the third round at Indian Wells, where she was beaten by sister Venus, before falling in the first round of the Miami Open to Japan's Naomi Osaka.
Following her latest withdrawal, it is unclear whether the 36-year-old American will start at the French Open, which begins on 27 May.