Tennis star Serena Williams has undergone surgery for a pulmonary embolism.  People Magazine is reporting that a blood clot was discovered in Williams' lungs last week and she had "emergency treatment Monday for a hematoma she suffered as a result"  of that treatment.

"Doctors are continuing to monitor her situation closely to avoid additional complications,"  Spokesperson Nicole Chabot tells People Magazine

Serena has not played a competitive match since winning Wimbleton last year.  She was sidelined after cutting her foot at a restaurant.