The McConnell campaign said the top Senate Republican would support the nominee, even if it isn't him.
"From day one, Sen. McConnell has committed to supporting the winner of the primary election," McConnell spokesman Allison Moore said according to the Kentucky newspaper. "The stakes of this election are too high to give President Obama another vote in the U.S. Senate with Alison Lundergan Grimes."
Bevin's campaign, meanwhile, did comment on the pledge.
Polling of the race has shown Bevin's chances of winning the nomination fading. In April, Bevin's campaign also lost a few staffers.
The Kentucky Republican primary is on May 20.
(H/t: The Hill)