(CNN)Just a day after House Speaker Paul Ryan endorsed Donald Trump, he turned around and blasted the presumptive Republican nominee for attacking the judge overseeing the Trump University lawsuit.

While explaining his endorsement Friday on a Wisconsin radio station, Ryan -- unprompted -- ripped Trump's attacks on the "Mexican heritage" of U.S. District Court Judge Gonzalo Curiel.

"Look, the comment about the judge, just was out of left field for my mind," Ryan said on WISN in Milwaukee. "It's reasoning I don't relate to, I completely disagree with the thinking behind that."
And then Ryan issued a warning to Trump, that he will speak out when he feels he needs to.
"So he clearly says and does things I don't agree with and I've had to speak up on time to time when that has occurred and I'll continue to do that if that's necessary -- I hope it's not," Ryan said.

Ryan's comments came shortly after Hillary Clinton's campaign slammed Trump in a statement for targeting the U.S.-born judge's Hispanic descent.
"The fact that Donald Trump doesn't see Judge Curiel and his family as Americans makes him unfit to be president of this great nation, a nation of immigrants," Lorella Praeli, director of Latino outreach for the Clinton campaign, said in a statement.