People magazine was the first to report that Serena suffered a pulmonary embolism last week and was seeing doctors at Cedars-Sinai Medical Center for the problem. It was discovered after she returned from New York for doctor's appointments relating to her foot issues.
"Monday Serena Williams underwent emergency treatment at Cedars [Medical Center] for a hematoma she suffered as a result of treatment for a more critical situation," a representative for Williams, Nicole Chabot, told the magazine.
Chabot said doctors are continuing to monitor the situation.
Earlier in the week, Serena said she had been targeting the French Open as her return to tennis. She hasn't played since last year's Wimbledon because of a foot injury suffered when she stepped on broken glass.
For now, Serena has more important issues to deal with than the timetable of her return to the court. Getting her health in order is priority one. Tennis can wait.
Update: Serena Williams released a statement about her condition later Wednesday:
"Thank you everyone for all of your prayers, concerns, and support. This has been extremely hard, scary, and disappointing. I am doing better, I'm at home now and working with my doctors to keep everything under control. I know I will be ok, but am praying and hoping this will all be behind me soon. While I can't make any promises now on my return, I hope to be back by early summer. That said, my main goal is to make sure I get there safely."
In another statement, her agents said the clot was caught in time and that Serena is resting at home under doctor's care.
There had been reports that the 13-time Grand Slam champion could miss up to a year. Her timetable seems more optimistic.
Follow Yahoo! Sports on Facebook and be the first to know about the most interesting stories of the day.
- Serena Williams