Former President Donald Trump jumped back into Pennsylvania’s Republican Senate primary, warning that the surging underdog Kathy Barnette “will never be able to win the General Election against the Radical Left Democrats.”

Yet in the same statement, Trump, who has endorsed Mehmet Oz for Senate, said Barnette could have “a wonderful future” in the GOP and that he would back her if she’s properly vetted.

”She has many things in her past which have not been properly explained or vetted, but if she is able to do so, she will have a wonderful future in the Republican Party — and I will be behind her all the way,” he said.

» READ MORE: Kathy Barnette is the surprise Pa. Senate candidate who just might win. Now she’s getting new scrutiny.

Trump concluded with another nod to Oz.

His statement comes as Barnette has rocketed into contention with Oz and David McCormick, seemingly gaining momentum in the campaign’s final days, with her rivals scrambling to do even basic research to to try to stop her.

”Dr. Oz is the only one who will be able to easily defeat the Crazed, Lunatic Democrat in Pennsylvania. A vote for anyone else in the Primary is a vote against Victory in the Fall!” Trump wrote.

» READ MORE: Pa. primary voter's guide: What to know about the races and candidates