Baucus, 72, previously announced that he won’t seek reelection to the Senate in 2014.

The news was first reported by Politico. Baucus aides declined to comment Wednesday evening when asked about the news outside the Senate Chamber.

Baucus’s ascension means there will be a vacancy in his seat. Gov. Steve Bullock (D) will get to make the appointment for the final year of Baucus’s term.