Eliza Collins

USA TODAY

Apparently endorsing Donald Trump is not a prerequisite for being considered as his running mate.

In an interview with Bloomberg Politics, Trump said that out of the four or five options he is considering, at least one is a former rival for the nomination who hasn't yet endorsed him (Ted Cruz? John Kasich? Trump didn't disclose names). During the interview, Trump, the presumptive GOP nominee, predicted the candidate in question will “come over to my side."

Trump said there are also at least two respected military officials being considered, but they are less likely to be chosen "because of the fact that I think I’m going to do very well on national security.”

Trump said that his own business acumen is enough, and it isn’t likely he’ll pick a business executive — and definitely not someone from Wall Street.

“No, no, I don’t think so," Trump said. "I don’t need that type of ability. I have that ability, better than they have.”

Trump said that he'd like to wait to announce his pick "the old fashioned way," which is at the convention. However, Bloomberg reports that some advisers worry he will make a rash decision and announce on Twitter.

What about former House speaker Newt Gingrich as chief of staff? Trump didn’t say what exactly he was considering him for but he had plenty of good things to say.

“Newt is a very talented guy. I don’t want to comment on what I’d consider him for. But Newt is a very talented guy, and great communication skills,” Trump said.

Gingrich has been a vocal supporter of Trump’s, except recently when he said Trump’s criticism of Judge Gonzalo Curiel was “inexcusable.” Trump responded by saying that he was surprised at Gingrich’s comments and that they were “inappropriate.”