Serena Williams spoke to the media today for the first time since news broke that she underwent emergency surgery for a hematoma—a gathering of blood under the surface of skin—related to a pulmonary embolism (blood clot in the lung).

The tennis star appeared on the Today Show to discuss what she called the "scariest moment" of her life:

Williams said the foot injury which kept her off the tennis court since July—and subsequently inactive with a boot on her foot—might have played a part in the development of the clots. She still has several clots in her lungs, but she said they should eventually dissolve, and that her lungs are "fairly healthy and on the road to recovery."

The 13-time Grand Slam champion said swelling in her leg and trouble breathing first led her to go to the hospital on February 18. Doctors found several blood clots on her lungs when she got a CT scan.

Soon after she was released from the hospital, Williams seemed to be doing fine. She even attended Academy Awards parties. When asked about why she attended the parties so soon after her release, she said:

"I had been through so much in the past 8 months, and it just had been so hard to work with. I really was kind of low on energy, but I was like, 'I gotta do something, kind of just to get my spirits up.' I wasn't doing so well mentally. I was just in my house, and just laying down and kind of just feeling terrible."

The following day she returned to the hospital for emergency surgery.

Williams was put on blood thinner injections which she says ultimately led to the growth of her hematoma.

"Usually your blood naturally clots around (the hematoma), but since I was on blood thinners it wasn't able to clot. So what started out as, like, a golf ball ended up being the size of a grapefruit on my stomach. So I had to get it drained, and when I got there, they were like 'we can't drain this. We have to surgically remove it.'"

She seems optimistic about her recovery, and said she hopes to return to the court this summer.

"Luckily enough, I was able to catch it soon enough that my career won't be affected," she said.