Simona Halep pulled out of the Qatar Open with a right foot injury shortly after she reached the semi-finals with a dominant 6-0, 6-4 win over American qualifier Catherine Bellis on Friday.
The Romanian world number two, who was playing her first event since losing in the Australian Open final last month, said she had been carrying the injury throughout the tournament and would also miss next week's Dubai Tennis Championships.
"Definitely until Indian Wells I will not play anything. I will decide before the tournament if I will be able to play," Halep told a news conference.
"I am surprised I could play three matches and win them. I felt pain every day, so it wasn't easy to manage it... the MRI shows that I have fluid and also tendinitis at the fourth toe, so I have to take care of it and think about my health first.
"I didn't have much time to recover before this tournament, but today was too much, and I decided to stop," added Halep, who joins Russian Maria Sharapova and American Madison Keys in pulling out of next week's event.
Halep's withdrawal means world number four Garbine Muguruza will play in Sunday's final in Doha after the Spaniard came back from a set down to beat Caroline Garcia 3-6, 6-1, 6-4.
After struggling to find her range and rhythm in the first set, Muguruza saved a break point and won five straight games in the second set to drag the contest into a decider.
She then broke Garcia early in the third set and held on to clinch the victory in nearly two hours.
Later, world number one Caroline Wozniacki suffered a mid-match blip before getting past Angelique Kerber 7-6(4), 1-6, 6-3.
She next faces the twice Wimbledon champion Petra Kvitova, who advanced after opponent Julia Goerges was forced to retire trailing 6-4, 2-1.
Nishikori reaches New York semi-finals with comeback win
Japan's Kei Nishikori survived his toughest test since his return to the ATP Tour, having to come back from behind to beat Radu Albot 4-6, 6-3, 6-1 on Friday to reach the semi-final of the New York Open.
Playing in his first ATP tournament since August, Nishikori had enjoyed straight set victories in the first two rounds before dropping the first set to Albot. But the 28-year-old regained momentum in the match by controlling his serve and breaking Albot's service six times.
"It was a very tough start. I think he was playing very good tennis," Nishikori was quoted as saying on the ATP Tour website.
"During the second set I started getting my rhythm back and started playing a little more inside the baseline and everything started working well... (I'm) very happy to win today."
Nishikori will now face South African Kevin Anderson who overcame American Frances Tiafoe 6-3, 5-7, 6-4 in a two-hour battle.
In earlier matches, second seed Sam Querrey topped Croatian Ivo Karlovic 7-6(5). 7-6(4).
He will meet Adrian Mannarino in the other semi-final after Mannarino overcame Spain's Adrian Menendez-Maceiras 7-5, 2-6, 6-3.
Nishikori suffered a right wrist injury in August which forced him to miss last year's US Open and the Australian Open at the start of the season.
The former US Open finalist has since made his comeback tocompetition by playing in Challenger events.
ATP says 'no evidence' against Harrison’s racist remarks
The ATP said on Friday it found no evidence that Ryan Harrison directed racist remarks at fellow American Donald Young during their stormy first-round match at the New York Open.
Young, who is black, made the allegations following his loss to Harrison on Monday during which the two players got into an argument at a change of ends. Harrison denied any wrongdoing.
The men's tour said it conducted a full investigation and that all available evidence was reviewed, including match footage and interviews with match officials and other tournament personnel who were in close proximity to the players.
"Unfortunately, the audio recording on the match footage did not pick up verbal exchanges between the players," the ATP said in a statement.
"At this time no evidence has been found to support the allegation that Ryan Harrison used a racial slur during the match."
Following his defeat world number 65 Young took to Twitter to offer his views on what had happened.
"I'm shocked and disappointed, Ryan Harrison, to hear you tell me how you really feel about me as a black tennis player in the middle of our NY match," Young said.
"I thought this was supposed to be an inclusive gentleman's sport."
Young did not elaborate on what was actually said between the pair, but world number 44 Harrison was quick to respond.
"The accusations made by Donald Young tonight following our match are absolutely untrue," said Harrison.
"I'm extremely disappointed that someone would say this in reaction to a lost tennis match. Any video/audio will 100 percent clear me and I encourage anyone with the available resources to find it."