NEW YORK -- Two days ago, it looked as though Venus Williams had been reborn at age 31. Now, we are left to wonder whether she'll be a major factor again in women's tennis.
Less than an hour before Wednesday's second-round match against Wimbledon semifinalist Sabine Lisicki -- the most anticipated match of this young tournament -- it was announced that Williams was withdrawing because of an unspecified illness.
A while later, that illness was specified in a stunning statement released by Williams:
"I'm really disappointed to have to withdraw from this year's U.S. Open. I have recently been diagnosed with Sjogren's Syndrome, an autoimmune disease which is an ongoing medical condition that affects my energy level and causes fatigue and joint pain."
The syndrome destroys the glands that produce tears and saliva and can affect the kidneys, lungs and blood vessels. The body mistakenly attacks healthy tissue. Complications -- although rare -- can include kidney failure, lymphoma and pulmonary infection.
Some 4 million Americans are afflicted with the condition, and nine of 10 are women.
"I'm speechless," said 18-time Grand Slam champion Chris Evert. "I thought she was looking really good. I'm disappointed for Venus, and I'm disappointed for the U.S. Open. She would have had to be 100 percent healthy to win this match."
The key word is healthy. Venus has been anything but most of the year. She has struggled with hip and knee injuries plus a lingering viral illness whose aftereffects may well have caused her to pull out. After beating Vesna Dolonts 6-4, 6-3 in the opening round, Venus was vague, even evasive in describing her illness and the specifics of her preparation for the U.S. Open. Now we know why.
"Was there an official diagnosis?" asked Peter Bodo of Tennis magazine.
"Yeah, there was," Venus answered.
"Which is " Bodo persisted.
"It's outside of the press room, that name," Venus said. "But it's good to be here."
Then, 48 hours later, she wasn't.
In retrospect, Venus' voice during the news conference sounded husky, as though she had a cold. Her energy level seemed low.
The condition, according to one expert, is not necessarily career-threatening.
"No, I don't think so," said Dr. Wesley Mizutani, the Chairman of Rheumatology at the Talbert Medical Group in Huntington Beach, Calif. "It's not like rheumatoid arthritis. With medication, Sjogren's can be controlled. The good news is that there is usually no permanent joint damage."
The real issue, according to Mizutani, is the fatigue factor. A professional tennis player cannot survive at anything less than maximum fitness. The effects of Sjogren's -- described Monday by Venus as "energy-sucking" -- can be mitigated by several medications.
Coincidentally, No. 6 seed Robin Soderling of Sweden pulled out of his first-round match with what was described by his agent as a viral illness.
Lisicki said she was surprised by Venus' withdrawal.
"I just found out, I don't know, half hour ago or so," Lisicki said. "I was getting ready for my match and was in the locker room. So, yeah, that's when the referee told me.
"I saw her, and I heard she practiced as usual. I saw her in her match clothes, so was fully prepared and really looking forward to the match.
"Yeah, I hope she will be fine quick."
Although she had played only 10 matches in eight months coming in, Venus looked good enough against Dolonts that people wondered whether she could make another run to the semifinals, as she did a year ago. The Williams sisters have come back so swiftly so many times that their success almost seems a given.
By contrast, Serena, who will turn 30 in late September, has had a spectacular return to the WTA Tour after missing nearly a year. She's 17-2 in matches since returning in June.
It has been 10 years since Venus won her second -- and most recent -- U.S. Open title at age 21. And although she reached the final four here a year ago, it seems an eternity has passed since then.
Serena might have had some inside information. On Monday, she was asked about the sisters' longevity.
"If Venus were to stop, I'd probably still keep playing," she said. "The way I feel right now, I definitely will still go. I never thought about when I would end or when I would stop.
"Definitely, as long as I'm healthy and doing well, I will keep going."
Venus, only 15 months older, is neither healthy nor doing particularly well.
"I think she'll probably kiss this year goodbye," Evert said. "I'd expect her to take the rest of the year off. She needs to rest her mind and body and maybe ask herself if she wants to do this for a full year next year."
Pete Sampras had just turned 31 when he beat Andre Agassi in the 2002 U.S. Open final. It turned out to be the final match of his career.
"I enjoyed playing my first match here, and wish I could continue but right now I am unable to," Venus' statement concluded. "I am thankful I finally have a diagnosis and am now focused on getting better and returning to the court soon."
Venus always has been a battler, and there has always been a sense that she enjoys the essence of the sport -- not necessarily all its trappings and rewards -- more than her sister.
Will she be able to continue at 31? The early returns, anyway, didn't seem optimistic.
Greg Garber is a senior writer for ESPN.com.