Montana Gov. Steve Bullock (D) has scheduled a Friday press conference after the confirmation of Sen. Max BaucusMax Sieben BaucusTop Lobbyists 2017: Hired Guns GOP tries to keep spotlight on taxes amid Mueller charges Clinton-Sanders tensions linger for Democrats MORE (D-Mont.) as U.S. ambassador to China, a sign he may follow through on his promise to act swiftly in appointing a Senate successor.

Bullock has been tight-lipped about his decision-making process, but many Democrats expect he'll name his 2012 running mate, Lt. Gov. John Walsh (D), to the seat. Walsh has been running for Baucus's seat for months and has Bullock's endorsement.

Democrats believe a Walsh appointment would improve the party's chances of holding onto the seat in the Republican-leaning state by helping him raise his name recognition around the state and boost his fundraising. Rep. Steve Daines (R-Mont.) has outperformed Walsh in fundraising, and the few polls of the race have found him with a solid lead.

Bullock didn't address the looming appointment in a Thursday statement following Baucus's confirmation, instead praising the longtime senator's career. But with a press conference set for the next day, it's likely he'll address, or even name a successor, at the 10 a.m. Mountain time announcement.

"I join all Montanans as we say congratulations and thank you to Max for his service to our state and nation," the governor said in a statement.

"Max has dedicated his life to serving the people of Montana," Bullock continued. "From his role establishing the CHIP program and unyielding dedication to protecting Montana’s mountains and prairies to his efforts to stop the privatization of Social Security, for the past forty years, Max has been at the forefront of the most important debates impacting Montana and our nation. I look forward to continuing to work with Max in his new role and am confident that his leadership in China will pay dividends for all Americans for years to come."