Arbitrators rule that a Russian figure skater can continue to compete at the Games.

The Russian figure skating star at the center of doping questions at the Beijing Olympics will be allowed to compete in the women’s singles event after a ruling by arbitrators on Monday.

The panel, in a statement, said it would be unfair and cause “irreparable harm” if she were barred from the competition, despite having tested positive for a banned substance in December. That revelation came last week, after she had helped lead Russia to a gold medal in the team event.

The skater, Kamila Valieva, 15, has become a face of the Games and is widely seen as the favorite to win the women’s event that begins on Tuesday.

At a practice session a half-hour after the ruling, she performed her jumps and spins, just as impeccably as usual, as more than a hundred journalists looked on. She left the rink, carrying a favorite stuffed rabbit toy, without speaking to them.

The ruling on Monday means she can take to the ice when the short program begins, though questions will surely hang over her performance and the Russian team, as well as the system for ensuring athletes are clean.

The panel ruled on a narrow question: whether Russia improperly lifted a suspension of Valieva last week, only one day after imposing it when it said it had received the findings of the doping test. Lifting the suspension effectively allowed her to compete in the singles event, which led three international organizations to appeal to the Court of Arbitration for Sport, the highest legal authority in global sports.

In making the decision, the panel’s statement said, it “considered fundamental principles of fairness, proportionality, irreparable harm and the balance of interests” between Valieva and the organizations seeking to bar her from the Games. Also, it noted, Valieva was a minor and did not test positive at the Beijing Games, though she could face penalties when her case is examined after the Olympics.

The panel was not charged with evaluating whether Russia should keep the gold medal in the team event it earned, largely through Valieva’s stunning performance. That medal, which has not yet been awarded to the winning athletes, remains in dispute and could take months to sort out. The United States won silver and Japan bronze.

Matthieu Reeb, the director general of the court, announced the ruling at a news conference in Beijing on Monday, less than 30 hours before the women’s event was to begin. He left the room after making the announcement without answering reporters’ questions.

Within minutes of the ruling, the United States Olympic and Paralympic Committee issued a statement expressing its disappointment. Sarah Hirshland, the chief executive of the committee, said that clean athletes are being denied “the right to know they are competing on a level playing field.”

“We are disappointed by the messages this sends,” Hirshland said, adding, “This appears to be another chapter in the systemic and pervasive disregard for clean sport by Russia.”

Tricia Smith, the president of the Canadian Olympic Committee, said it was “extremely disappointed” with the result; Canada won fourth in the team event.

Other entities in Olympic sports were also upset by the ruling and denounced allowing Russian athletes to compete at these Games in the first place. Russia was caught orchestrating a state-sponsored doping scheme at the 2014 Games in Sochi, Russia, and only its athletes who clear special antidoping protocols are allowed in Beijing.

“Russia has never been incentivized to reform because sport leaders favored politics over principle and rebranding over banning,” said Rob Koehler, the director general of Global Athlete, an athletes’ advocacy group.

The court panel on Monday did not decide whether Valieva was guilty of knowingly using a banned drug. But it did question the timing of the events, saying there were “serious issues of untimely notification of the results.”

In the ruling, the arbitrators rejected appeals by the International Olympic Committee, the World Anti-Doping Agency and skating’s global governing body to reinstate the provisional suspension Russia had imposed.

Valieva had tested positive for trimetazidine, a heart medication that could increase endurance. Her positive result came from a urine sample that was taken from her at the Russian national championships on Dec. 25 but was not confirmed for about six weeks.

The Russian antidoping agency said it had received notice from a Stockholm lab of Valieva’s failed drug test only on Feb. 7, the same day that she led the Russians to a gold medal in the team event.

“This is a very complicated and controversial situation,” her coach, Eteri Tutberidze, told Russia’s state-run TV network Channel One on Saturday in her first public comments about the case. “There are many questions and very few answers.”

Despite those unknowns, Tutberidze added, “I wanted to say that we are absolutely confident that Kamila is innocent and clean.”

The legal battle over Valieva’s future eligibility is likely to last for weeks, at least. The fate of the Olympic gold medal in the team event also hangs in the balance.

In last week’s free skate in the team competition, Valieva became the first woman to land a quadruple jump. Her performance led the Russians to win the team event, their best showing ever.

Decisions on whether Valieva will face any penalties for the doping test in December, and whether Russia will be awarded the team gold, will probably come after the Olympics.

Because she is only 15 she is recognized as “a protected person” under antidoping rules, so her case will meet different standards of evidence and she would face lesser penalties, if any, than adults would. It is also possible that she could receive only a reprimand for using the banned drug or for having it in her system.

The people more likely to face punishment would be any of her coaches, trainers and medical personnel who might have known about her using the drug, or who might have given it to her.