Brittney Griner’s trial nears an end with closing arguments.

The trial of Brittney Griner reached its final stage on Thursday, with the American basketball star appearing in a Russian court for the start of closing arguments in a case that is expected to end with the conviction of Ms. Griner, who has been caught up in the deep crisis between Moscow and Washington over Russia’s invasion of Ukraine.

The verdict and sentencing are expected to be announced on Thursday evening, according to Maria Blagovolina, a partner at Rybalkin Gortsunyan Dyakin and Partners law firm who is representing Ms. Griner. Her defense team had previously said it expected the case to finish by mid-August.

Ms. Griner has been in custody in Russia since Feb. 17, accused by the Russian authorities of having a vape cartridge with hashish oil in her luggage at an airport near Moscow. The drug charges she faces carry up to 10 years in prison under Russia’s criminal code, and prosecutors in her case asked for a sentence of nine and a half years. They also asked for a fine of 1 million rubles, about $16,600.

During one of the initial hearings in her case, Ms. Griner pleaded guilty to the charge but insisted that she had not intended to break Russian law. Under the Russian judicial process, the trial proceeded, with her lawyers presenting evidence aimed at softening the eventual sentence.

In comments to the court on Thursday, Ms. Griner talked about her upbringing in Houston, the values her parents instilled in her, including “take ownership for your responsibilities.’’

“That’s why I pleaded guilty to my charges I understand everything that has been said against me in the charges against me, but I had no intent to break Russian law,’’ she said. “I want the court to understand that it was an honest mistake that I made while rushing and in stress trying to recover post-Covid and just trying to get back to my team.’’

The defense team for Ms. Griner, an Olympian who plays for the Phoenix Mercury W.N.B.A. team, has been trying to persuade the judge to be lenient. “I’d like to ask the court to acquit my client but, if the court deems this impossible, I think that the penalty should be handed down with due account of Griner’s personality and the role she has played in the development of Russian basketball,” Ms. Blagovolina told the court on Thursday. “There should be a milder penalty.”

But Ms. Griner’s fate is subject to diplomatic bargaining. Russia and the United States have been exchanging signals that she and another American held in Russia could be part of a prisoner exchange involving a Russian imprisoned in the United States.

Russian officials have said that no progress in those negotiations can be made before the court completes her trial.

Aleksandr Boikov, one of Ms. Griner’s lawyers, said on Wednesday that the defense would deliver its closing arguments on Thursday, since it has finished its case and does not plan to call any additional witnesses. He said that Ms. Griner would have the opportunity to make a final statement, and that then Anna S. Sotnikova, the judge, would begin forming her verdict.

The Biden administration has been under pressure from Ms. Griner’s wife and supporters to negotiate her freedom.

Last week, Secretary of State Antony J. Blinken said that the U.S. government had “put a substantial proposal on the table” to the Russian side regarding Ms. Griner and other Americans held in Russian custody. Mr. Blinken then discussed the matter with his Russian counterpart, Sergey V. Lavrov, last week, in their first phone call since Russia’s invasion of Ukraine, but no breakthroughs were reported.

Russian officials have insisted that the diplomatic wrangling over Ms. Griner should remain behind closed doors. Dmitri S. Peskov, the Kremlin’s spokesman, said on Tuesday that negotiations over a potential prisoner exchange “should be discreet.”

“Megaphone diplomacy and the public exchange of opinions will not lead to any result,” he said.

Ms. Griner arrived in a Moscow airport on Feb. 17, on her way to the Russian city Yekaterinburg near the Ural Mountains, where she had been playing for a local team during the off season. Customs officials checked her luggage, where they found two vape cartridges containing less than one gram of hashish oil.

News of her detention was made public only after Russia invaded Ukraine a week later. Ms. Griner, 31, was charged with an attempt to smuggle a significant amount of banned narcotics into Russia.

She testified during the court hearings that the illegal substance had been in her luggage as a result of an oversight while packing in a hurry. Her defense team noted that she was authorized to use medicinal cannabis in Arizona to manage pain, which has become a common practice among some American athletes.