Mark Cuban. AP Photo/Alex Brandon

Mark Cuban told Fortune Thursday that Donald Trump reached out to him directly after the billionaire owner of the NBA's Dallas Mavericks became increasingly involved in the political discussion.

"Yes, directly," Cuban said, when asked if he had heard from Trump. "To ask me why I have gone far more negative."

"I won’t tell you what I said," he added.

Cuban has chastised Trump in recent weeks, although he's expressed interest in serving as either Trump's or Hillary Clinton's running mate in the fall.

Clinton, the presumptive Democratic nominee, expressed an openness to the idea herself on an episode of NBC's "Meet the Press" last month.

The star of ABC's "Shark Tank" has ripped Trump over his perceived financial standing and lack of knowledge. This week, he said Trump would be a "puppet president" and tweeted that the presumptive Republican nominee will have to "grovel" for campaign donations.

During an interview with CNN's Don Lemon Thursday night, Cuban said he thinks Trump "has absolutely no self-awareness" when asked about the Manhattan billionaire's attacks on a federal judge over his Mexican heritage.

"I think he loses context continuously," Cuban said. "I think he gets caught up in his own head and thinks — you know, he hears what he's saying and thinks it's right no matter what he says. And it comes out stupid a lot of times."

Trump's latest self-inflicted firestorm centers around the real-estate magnate attacking US District Court Judge Gonzalo Curiel, who Trump said cannot fairly preside over a civil case involving Trump University, his now defunct for-profit real-estate school, because he is of Mexican descent and Trump will be "building a wall" along the US-Mexico border if elected in the fall.

Curiel is from Indiana.

Republicans from all sides of the party have publicly condemned the remarks and demanded that Trump change his tone. In a Tuesday-afternoon statement, Trump took a step back from the attacks but did not apologize. He made no mention of his attacks against the judge in his scripted postprimary speech later that night.

The blowback from the attacks may have been evident in a Thursday Fox News poll, which found that Trump had dipped 6 percentage points since last month in a head-to-head with Hillary Clinton — including dropping a whopping 11 points with independent voters.

However, polls have found that the majority of Republican voters do not find the attacks to be racist. Half of all voters polled in a Morning Consult poll released Friday said the comments were racist, while 35% said they were not.

During his interview with Lemon, Cuban said the comments were racist, but that Trump himself is not racist.

"Do I think he's racist in these comments? Or are they racist comments? Yes," he said. "In my experience with Donald Trump, my one-on-one experience, I don't think he's racist. Yes. I mean, if I thought he was truly racist and this is exactly what we were going to see from him as the president — then, yes, I preclude him immediately. I don't think he's racist. I think he has absolutely no self-awareness."

Cuban has kept his cards close to his chest when it comes to which candidate he will vote for in the fall as he publicly campaigns to be considered by either as a potential vice president. On Friday, Cuban told Fox Business that "there's a good chance I'll vote for Donald Trump" if Clinton picks Massachusetts Sen. Elizabeth Warren as her running mate.

"We need to be more center," Cuban said. "This country needs solutions, right? We don't need headline porn."

"Elizabeth Warren has accomplished a lot in her life, but taking it that far left would be a huge mistake, any more than if Donald Trump went the other way," he continued. "We need to come center."