Serena Williams is recovering in a Los Angeles hospital after undergoing emergency treatment for a blood clot in her lungs, People magazine reported yesterday.

Tennis officials were unable to confirm the report but a representative for the 29-year-old Williams told the magazine she was treated on Monday after falling ill.

The former world No. 1 has not played competitively since winning last year’s Wimbledon title after cutting her foot on broken glass at a restaurant in Germany.