A spokesperson for the senator did not respond to a request for comment. The New York Times was the first to report Inhofe might resign early.

By announcing before March 1, Inhofe will trigger an election this year to replace him. But he intends to stay in his seat until next January, avoiding the need for an interim appointment to fill his seat temporarily.

Inhofe is one of the most conservative members of the Senate, but embraced a deal-cutting acumen on two key policy areas: Infrastructure and national security. As the top Republican on the Environment and Public Works Committee, he enjoyed a close relationship with former Sen. Barbara Boxer (D-Calif.), a staunch liberal. Similarly, as the top Republican on Armed Services, he has worked amiably with Chair Jack Reed (D-R.I.).

Ahead of his pending announcement, there’s already a crop of people seen as potential candidates for the soon-to-be-vacated seat, including Oklahoma Gov. Kevin Stitt, who has increased his national profile over the past two years. There’s also state Lt. Gov. Matt Pinnell, former Oklahoma House Speaker T.W. Shannon, who ran for the state’s open Senate seat in 2014, and former U.S. Attorney Trent Shore. Reps. Markwayne Mullin and Kevin Hern are viewed as likely contenders, as well.

Sen. Roger Wicker (R-Miss.) is in line to succeed Inhofe on the Armed Services Committee, setting him up to chair the panel if Republicans retake the Senate. Wicker is currently the top Republican on the Senate Commerce Committee, and Sen. Ted Cruz (R-Texas) could be in line to take the top GOP slot on Commerce if Wicker moves on.

Alex Isenstadt and Andrew Desiderio contributed to this report.