Serena Williams is awaiting the results of scans on the leg injury that forced her to withdraw during her first-round match at Wimbledon on Tuesday.
The 23-time Grand Slam champion flew home to the United States the following day and was walking, which her coach, Patrick Mouratoglou said is a "good sign."
"We don't know for the moment; we are expecting the result of the clinical assessment," Mouratoglou told TennisMajors.com. "The manual test gave us an idea of the nature of the injury, not how serious it is. We're waiting to see how long she's supposed to be resting and, obviously, the consequences in terms of preparation for the next one [the US Open]. Time will fly. She's walking, which is a good sign, and it excludes very bad possibilities."
Williams retired at 3-3 in the first set of her match with Aliaksandra Sasnovich of Belarus after slipping on Centre Court while leading 3-1.
Mouratoglou said Williams, 39, who is trying to equal the Grand Slam record of 24 held by Margaret Court, was already trying to look ahead.
"I must say that Serena spontaneously turned the page," he said. "It was just the two of us driving out of the stadium, and her only questions were how to bounce back.
"'What's the next step? Where should we do the MRI? etc.' She was in the solution mode. Rewriting the story was not her business. That's why she's so strong."
Mouratoglou said the injury had been even more disappointing because both he and Williams believed she was in the right kind of shape, physically and mentally, to win Wimbledon for an eighth time.
"Absolutely, she was," he said. "It wasn't always the case in recent times. For instance, she was not ready enough for the French Open. She was absolutely ready at the Australian Open, where she moved very well [and reached the semifinals].
"What she missed is what leads her to be Serena. I mean, refusing to lose and suddenly playing at another level in the crucial moments. For a couple of years now, my quest [has been] to understand why she couldn't rely on that anymore.
"Now I found it, and it was the day before the first round. Serena was ready to show it at Wimbledon. I know her by heart, she was that strong at the beginning of the match and she was ready to use what I consider as a superpower when needed.
She felt that also.
"In her head, she was going to win the trophy. Her preparation had been very good. She was ready tennis-wise, physically, and mentally. In the first rallies, the energy was so good, so much better than Roland Garros."
Williams left the court in tears after the withdrawal, and Mouratoglou suggested it was partly because she does not know if she will be back.
"She'll be 40 soon; she doesn't know how many Wimbledons she will play in the future," he said. "Probably not that many, you can't be sure there will be another one. So many feelings going on in her head in a small amount of time."
Williams' injury was one of several to affect players at this year's Wimbledon with the courts seemingly a little greasier than usual, in part because the roof was closed for significant periods of time on Days 1 and 2, when the grass is always at its most lush.
Mouratoglou said Wimbledon needs to look at its policy regarding grass-court shoes, which does not allow shoes to have pimples on the sides.
"You have to know that most of the falls on grass are due to a [lack of] side support," he said. "When the players change direction, their reflex is to push the inside of the foot. That was clearly the motion in the falls of Adrian Mannarino [who also quit against Roger Federer] and Novak Djokovic.
"If you don't have pimples there, the foot gives way and here comes the splits. I really think a serious discussion must start on this topic with reconsideration for the player's health as a top priority.
"My point here is a global observation, concerning issues we have also had in previous years. Serena's slip was on the bottom of her foot, let's be clear. But shoes with pimples on the sides are the way to keep the players standing on grass."