Griner, one of the world’s best basketball players, was detained in Russia on what customs officials described as drug charges. Fans are worried.

When Brittney Griner is on the basketball court, everyone knows. At 6-foot-9, she towers over most other players. She snatches rebounds over her opponents’ outstretched arms, and her teammates know the surest way to score: Deliver the ball to her.

Since the Phoenix Mercury drafted Griner No. 1 overall in 2013, she has become one of the most dominant players ever: a seven-time All-Star, a W.N.B.A. champion and a two-time Olympian with matching gold medals.