CLEVELAND — Former President Donald Trump will battle Ohio’s old-guard Republican establishment in the closing days of the state’s competitive GOP Senate primary.

Trump announced late Monday that he will headline a Saturday rally near Dayton aimed at pushing his preferred candidate, Bernie Moreno, across the finish line. 

Buckeye Values PAC, a pro-Moreno group, will host the event, set for three days before the primary featuring Moreno, state Sen. Matt Dolan and Ohio Secretary of State Frank LaRose. There have been few independent polls gauging the state of the race, but the campaigns are treating it as a dead heat, with millions of dollars flooding the Buckeye State’s airwaves and nasty attacks among the candidates escalating.

A source close to Trump’s team told NBC News earlier this month that a rally for Moreno was “highly unlikely.” It was unclear Monday what had changed the political calculus. But the announcement comes after several high-profile endorsements for Dolan. Hours earlier Monday, Ohio Gov. Mike DeWine and his wife, Fran, declared their support for Dolan. Former Sen. Rob Portman, whose wife had been raising money for Dolan, offered his endorsement last week.

“Matt Dolan has a vision for the future. He listens. He fights. And, he knows how to get results for Ohio,” DeWine said in an open statement to Ohio voters. “We have worked to bring business to Ohio and to create an environment in this state that will continue to grow jobs and keep Ohio moving forward. Matt has been a real partner to make Ohio a national leader in economic growth, job creation, and innovation. He is fighting and winning to bring jobs to Ohio and secure a prosperous economic future for our children and grandchildren.”

DeWine has not tightly tied his political identity to Trump. The former president endorsed his 2022 reelection bid — but only after a primary in which DeWine faced a challenge from the right. Dolan, too, has avoided getting too close to Trump. He presents himself as a champion of Trump policies but has acknowledged that the two are not in sync, personality-wise.