British number one Johanna Konta will miss this month's WTA Finals after withdrawing from next week's Kremlin Cup with a foot injury.
The 26-year-old world number 10 had to reach the final of the Moscow event in order to secure a place at the Singapore season finale which features the top eight players in the world.
Konta suffered the injury prior to the Hong Kong Open earlier this month.
Until then, the Briton had held the last WTA Finals qualifying spot.
A losing streak which extended to five matches with a first-round defeat at the China Open saw her displaced by Frenchwoman Caroline Garcia, who has won her last two tournaments.
Despite missing out on the WTA Finals, which begin on 22 October, Konta is still in line to qualify for the WTA Elite Trophy, which gets under way on 31 October in Zhuhai, China.
The Elite Trophy features 12 players - those ranked from ninth to 19th, plus one wildcard.
Konta could also travel to Singapore as an alternate for the WTA Finals, a role she took up last year after missing out by one position on a place in the top eight.
"Jo's participation in both events is under review with her team and her medical advisors," said a statement from her management.
WTA Finals line-up:
1. Simona Halep (Romania)
2. Garbine Muguruza (Spain)
3. Karolina Pliskova (Czech Republic)
4. Elina Svitolina (Ukraine)
5. Caroline Wozniacki (Denmark)
6. Venus Williams (USA)
7. Jelena Ostapenko (Latvia)
8. Caroline Garcia (France)
Russell Fuller, BBC Tennis correspondent:
Konta's injured left foot is not thought to be a long-term problem, and it is still possible she will travel to Singapore as first alternate, and also compete in the second tier end-of-season event in Zhuhai the following week.
Both are potentially very lucrative and offer a high number of ranking points, but Konta may yet decide rest and recovery would be a better recipe.
Five consecutive defeats have made this a stressful period for her, but it has still been a hugely successful season.
She won the prestigious Miami title for the first time, became the first British woman to reach a Wimbledon semi-final for 39 years, and as a result reached number four in the world rankings.