The trip is likely to occur in the next few weeks.

Richardson, who also previously served in Congress as ambassador to the United Nations and energy secretary, has a history of working to facilitate prisoner releases and mediating international conflicts. He runs The Richardson Centre for Global Engagement.

Recently, he assisted in bringing former US marine Trevor Reed back from Russia, where he was held for more than two years.

Griner, the all-star centre for the Phoenix Mercury, was taken into custody in February after officials at a Russian airport said she had vape cartridges containing hashish oil in her luggage. She entered a guilty plea in court last week and said she packed the items accidentally.

Experts said an admission of guilt is typically required for Russians to engage in talks to release a prisoner.

Richardson is working with the Griner family and also represents Paul Whelan, an American who has been detained in Russia for more than three years. He is working on Griner’s case independently of the White House, per the report.

“We asked the Richardson Centre to help and I’m encouraged that he might be going,” Cherelle Griner, Brittney Griner’s wife, said in a statement to ABC News yesterday.

A “Bring BG Home” rally held at the Mercury’s home arena in downtown Phoenix attracted teammates and supporters, many of them wearing “We are BG” shirts in support of the two-time Olympic gold medalist.