"This is the bluest of blue states. It's an uphill climb," said Stone, who chaired Trump's presidential exploratory committee in 2000 and worked as a strategist on the bombastic billionaire's aborted White House bid last year.
Stone described a 2016 presidential run as a "better race" for Trump and that they've already discussed the possibility of it.
"Last New Year's Day, this is a year ago essentially ... he called me ... and he'd just come in from playing golf and he said, 'You know, I figure 2016 is my last shot. After that, I really will be too old, but I feel good I'm at the top of my game,'" recounted Stone.
He said he and Trump "went through the whole list" of potential 2016 Republican candidates and Trump "concluded that he's the strongest."
However, Stone also offered some tough talk to his longtime friend in light of Trump's past history of toying with campaigns.
"I said, 'Donald, you've been back to this well so many times,'" said Stone. "'If you're going to do it, you have to do it. You keep doing the big tease.'"
Stone said he also warned Trump that there's more to a presidential race than getting your name in the press.
"I've tried to say to him, 'Look, I just don't think you understand the lifestyle change that running for President requires,'" Stone said. "'You don't like shaking hands. ... You don't like stumping. You just want to come in and do press stuff. It just doesn't work that way.'"
In spite of these critiques, Stone said he'd definitely be willing to serve as a strategist if Trump gets involved in the 2016 presidential race.
"I'm essentially a mercenary," said Stone.
Still, one of Trump's other advisers, Michael Cohen, told TPM on Monday that the real estate mogul is seriously considering the New York gubernatorial run.
"I would say that it is certainly a consideration at this time," said Cohen, who serves as Trump's special counsel and executive vice president at his company, the Trump Organization.
But when asked about Trump's reputation for throwing his name out there as a potential candidate as little more than a publicity stunt, Cohen insisted Trump political aspirations were serious.
"If in fact Mr. Trump announces that he will run for the governorship, mark my words, if he does that he will be 100 percent committed to not just running, but to winning," Cohen declared.
Cohen also said unspecified "personal reasons" were behind Trump's decision not to run for president last year.
"For a multitude of reasons, he elected not to proceed, but at no point in time, had he ever declared that he was running. He didn't do like a Ross Perot, run then pull out, run then pull out," Cohen said. "It was a consideration for him, and don't forget at the time that he did elect not to run for the presidency, he was leading in the polls, there were other personal reasons why he didn't."
Despite an initial slip, Cohen also rejected the notion Trump's past political flirtations were insincere.
"First of all, the fact that he considered running for the highest office in the land is not something that he or anybody should take serious," said Cohen before catching himself and reversing course. "Should not take, you know, seriously."