Serena Williams Recovering From Blood Clot

Tennis star Serena Williams, 29, was living it up at Elton John's post-Oscar bash Sunday night, but she was admitted to L.A.'s Cedars Sinai Medical Center the next day for emergency treatment on a hematoma in her lungs.

Williams had been treated for a pulmonary embolism last week, reports People. Nicole Chabot, a spokesperson for the tennis player, said that Monday's hematoma was the "result of treatment for a more critical situation …. She had been in New York for doctor appointments for the ongoing issues with her foot."

Williams chimed in on her condition on her Twitter account Tuesday night. "Tough day," she tweeted. She is set to return to training this season and compete in the Sony Ericsson Open in Key Biscayne in late March. Tournament director Adam Barrett told the Miami Herald that he doesn't expect her to play. —KIMBERLY STEELE