Straczynski, who is best known for creating the space opera, its spin-off Crusade and shows like Jeremiah and Sense8, addressed Doctor Who's new vacancy on Twitter, revealing that he'd take on the new role "in a heartbeat".
"I don't know if the BBC would ever consider an American to show-run #DoctorWho, but if so, I would be there in a heartbeat," he said.
"(Well, technically two heartbeats, since two hearts...)," he added.
Chibnall and Whittaker, who'd previously worked on Broadchurch together, will bow out after Doctor Who's upcoming six-part series, two specials and a final feature-length adventure starring the Thirteenth Doctor.
With the recent departure of Bradley Walsh and Tosin Cole, who played The Doctor's companions Graham O'Brien and Ryan Sinclair respectively, the new series will see Whittaker's Doctor head out on a set of new adventures alongside Yaz (Mandip Gill) and new sidekick Dan Lewis, played by comedian John Bishop.