Richardson told Jake Tapper on Sunday’s “State of the Union” that he’s working with the families of both Americans while coordinating with the White House and that he’s optimistic.

"I am cautiously optimistic on the Griner (and) Whelan negotiations," said Richardson,  the former governor of New Mexico who has a long history of working to free Americans detained overseas. He is representing both the Griner and Whelan families.  

Tapper asked if Griner and Whalen would be freed by the end of this year. Richardson sounded confident.

“I do think so. Now, I hate making predictions, but yes,” Richardson replied. 

“I know (the families are) very emotional and this is a very emotional time. All I can say is that the Biden administration is working hard on it. So am I," Richardson said. "We coordinate, but not always agree on every tactical decision. But I’m not going to interfere in their process. I’m just giving you my assessment after two visits to Russia on behalf of American hostages.”

The White House said last week that it has yet to receive a "serious counter-offer" from Moscow though Richardson told Tapper he sensed from the Russian officials he met that Moscow is "ready to talk." 

Read more about Griner's Russian basketball career: Why Aren't Russian Billionaire Owners Of Brittney Griner's Basketball Team Helping Get Her Out Of Prison?

Whelan was sentenced in 2020 to 16 years in jail after being convicted of spying, charges he has denied.