"We need to come together and help do whatever we possibly can to bring BG home quickly and safely!! Our voice as athletes is stronger together," James said in a Tweet on Sunday night.
James also shared a message from Uninterrupted, urging President Joe Biden and Vice President Kamala Harris to take action and help get Griner home.
The two-time Olympic gold medalist was arrested in February at a Moscow airport while playing for UMMC Ekaterinburg during the WNBA offseason.
Russian authorities claimed to have found cannabis oil in Griner's luggage and accused her of smuggling significant amounts of a narcotic substance, an offense punishable by up to 10 years in prison.
In May, a Russian court extended the 31-year-old athlete's pretrial detention until at least June.
Last week, the Women's National Basketball Players Association (WNBPA) marked the 100th day of her detention in Russia by renewing calls for Griner's release.
The State Department has classified Griner as wrongfully detained in Russia and her case is now being handled by the office of US Special Presidential Envoy for Hostage Affairs (SPEHA) Roger Carstens, a State Department official confirmed to CNN last month.
The SPEHA office leads and coordinates the government's diplomatic efforts aimed at securing the release of Americans wrongfully detained abroad, and the shift to their office means more flexibility in efforts to negotiate her freedom, as they do not necessarily have to wait for Russian legal proceedings to play out.