Pelosi, who has officially remained neutral, was even more blunt during an earlier news conference on Capitol Hill.
"I just don't think it's going to happen," she said, saying her political gut told her such an arrangement between two former rivals would be "impossible."
"Take it from me, that won't be the ticket," Pelosi stated emphatically.
Obama gave a noncommittal answer when pressed on the subject Thursday while campaigning in Boca Raton, Fla., saying he would be like Abraham Lincoln and consider his rivals for top administration jobs.
"I want to know if you'd consider everybody who is a possible help to you as a running mate," a Pompano Beach voter asked. "Even if his or her spouse is an occasional pain in the butt."
The candidate initially laughed off the query but then replied, "My goal is to have the best possible government. And that means me winning. So, I'm very practical in my thinking. I'm a practical guy."
On the other side of the aisle, Arizona Sen. John McCain will host several Republican vice presidential contenders at his home in Sedona, Ariz., this Memorial Day weekend.
Gov. Bobby Jindal of Louisiana, Gov. Charlie Christ of Florida and former Gov. Mitt Romney of Massachusetts have all been invited to spend some leisure time with the presumptive Republican presidential nominee.
McCain campaign senior adviser Charlie Black insists the gathering is purely social.
"It has nothing whatsoever to do with the vice presidential selection process," Black said, dismissing speculation that it is a running mate audition by noting that would be "pretty awkward" to have all of the contenders together at the same time.
McCain has assembled, according to Stephanopoulos on today's "Good Morning America," a list of 20 potential vice presidential candidates. That list includes New York City Mayor Michael Bloomberg, a Democrat who became a Republican and then, earlier this year, became an independent.
Bloomberg, a multimillionaire who considered a third-party candidacy, has met with McCain and Obama in the course of the campaign.