"If I decide to run for president as an independent, I will believe and have the conviction and the courage to believe I can win," Schultz said. "I can't answer that question today. But I certainly am not going to do anything to put Donald Trump back in the Oval Office."
Schultz faced a battering earlier in the day from top Democrats and political strategists, who criticized the billionaire for pursuing a long-shot campaign that some described as a vanity project.
A lifelong Democrat, Schultz said on Monday that he no longer identifies with the party because he sees it moving too far to the left on issues including government spending and health care.
One high-profile, if indirect, criticism came from Michael Bloomberg, the former mayor of New York, who has belonged to both the Republican and Democratic parties and has been floated as a possible presidential contender in 2020.
"Given the strong pull of partisanship and the realities of the electoral college system, there is no way an independent can win. That is truer today than ever before," Bloomberg said in a statement that did not mention Schultz by name.
"In 2020, the great likelihood is that an independent would just split the anti-Trump vote and end up re-electing the President. That's a risk I refused to run in 2016 and we can't afford to run it now," the statement said.
Schultz said that he had "tremendous respect" for Bloomberg, "but I don't agree with his conclusion."
"Most people don't realize that about 42 percent of the electorate affiliate themselves as an independent," Schultz said. He said that his own analysis was based on "facts, not things that are made up."