Serena on the mend after being treated for blood clot

Winner of 13 Grand Slams could be out of action for a year due to illness

Serena Williams' absence from tennis could stretch to almost a year after two new health scares - a blood clot in a lung followed by a hematoma - have added to her injury woes.

Her agents confirmed on Wednesday that Williams was diagnosed with a pulmonary embolism last week and later needed treatment for a hematoma. The 13-time Grand Slam champion hasn't played an official match since winning Wimbledon last July because of a foot injury she sustained at a restaurant.