Kansas Republican Sen. Pat Roberts will not seek re-election in 2020, he announced Friday.

“I will serve the remainder of this term as your senator, fighting for Kansas in these troubled times,” he said. “However, I will not be a candidate in 2020 for a fifth Senate term.”

The 82-year-old Roberts announced his decision at the Kansas Department of Agriculture in Manhattan, Kansas — a symbolic location after he shepherded the farm bill to passage weeks ago.

Roberts is forgoing what could have been a difficult re-election bid. He survived a GOP primary in 2014, winning fewer than 50% of the vote. And Democrat Laura Kelly won the Kansas governor’s office last year, giving Democrats hope they can compete statewide there.

His retirement is likely to create a crowded field of Republicans vying for the seat.

The national GOP is eying Secretary of State Mike Pompeo, a former Kansas congressman, as a possible recruit, one Republican source said.

“Pompeo is in a league of his own. Republicans in the Senate writ large would love to see him run,” the source said. “The list is him, and then there’ll probably be a second list depending on where his head is at.”

A source with knowledge of Pompeo’s thinking said, “He’s happy to be mentioned. Focused on doing his job as (secretary of state).”

“I think we have so many good people that could take over,” Roberts said. He said the party has good candidates “inside the congressional delegation and outside the congressional delegation.”