Virginia Governor Tim Kaine and Indiana Sen. Evan Bayh are reportedly not the selected candidates, according to the Associated Press.
And little-known Texas Congressman Chet Edwards has been added as one of the potential prospective Obama running mates. Edwards joins a small circle - three to four politicians - whose names have already been mentioned.
Obama says he has already chosen his running mate, but that remains a closely guarded secret. For some, Sen Hillary Clinton is still the best choice, although it appears she may not be Obama's choice.
"I kind of thought it would be kind of neat if it would be Hillary. But I like Obama and I support him. That's where I go with it," said Karen London, Obama supporter.
Obama says he has picked a vice-presidential running mate but won't say who, opting to make his decision known first by text message or e-mail to those who signed up to receive the announcement.
Obama campaigned with Kansas Governor Kathleen Sebelius, one of several prospective politicians, along with Senator Joe Biden of Delaware and Indiana Senator Evan Bayh on Obama's short list.
Insiders say it's unlikely Obama's vanquished rival Clinton would emerge as his choice for number two. According to some political experts, the choice for vice president has little effect on how and who the public votes for.
"I know it's interesting to speculate on this, but the final decisions that make an individual choose one candidate or the other have relatively little or nothing to do with who the vice president is," said Prof. Alan Gitelson, political scientist, Loyola University.
Once Obama makes his announcement, he and whoever he chooses will head to Springfield for a rally Saturday.
The very fact that a bunch of little gizmos are the tools of notification on something as big as a running mate demonstrates that technology is taking over political campaigns at a speed few ever imagined. It's the key to Obama's prodigious fundraising and the rapid audio and video responses to every gaff or attack on the campaign trail.
And some time between now and Saturday afternoon, it'll tell us who wins the Obama veep-stakes.
The political world may have been in a state of high anxiety Friday, but Obama ignored all of that as he left his South Side home in gym clothes for a morning workout. But he was in a suit Friday afternoon to work on his convention speech while his top advisors, like Valerie Jarrett, who appeared on ABC7 Friday morning, maintained the veil of secrecy that is still shrouding his vice presidential choice.
"It's a funny thing. We have decided that the first people who are going to learn are the supporters," said Jarrett.
The souvenir shop at Obama's Illinois office in Chicago's West Loop still didn't have any buttons or t-shirts or bumper stickers or yard signs with the name of the new dream ticket Friday afternoon.
The short-list hopefuls went about their business Friday. Indiana Senator Evan Bayh took a jog. Virginia Governor Tim Kaine hung out with his family, htough by Friday night sources had told the Associated Press he was not the candidate.
And Edwards talked about the recent speculation that he may be the one.
"I'm honored to have been considered by the Obama campaign in this process. But there's only one person that makes this decision, and regardless of what that decision is, I'm going to be strongly supportive of senator obama for the presidency and his choice for V.P," said Edwards.
Another report Friday raised some eyebrows by claiming Obama's vice presidential team never interviewed Clinton or requested any documents, which is fueling speculation that she's never even been considered for the VP spot.
"I thought it would be neat if it would be Hillary, but I like Obama and I support him," said Judith Tancula, Obama supporter.
"When you go on the plane, Andy, no one ever asks, 'Who is the co-pilot?' That has not meant anything since 1960. I think in 1988, when George Bush picked Dan Quayle, that showed you how irrelevant the VP pick is," said Paul Green, Roosevelt University.
The ABC political unit is reinforcing Professor Green's analysis with polling data on the last few presidential campaigns. And when you put it all together, the net benefit of a specific choice of running mates is plus one percent.
In Springfield Friday, crews worked to get ready for Saturday's rally. They've been building the staging area and setting up risers around the old state capitol. Thirty-thousand people are expected to attend the event. For those who are far from the stage, a giant screen will be set up. So no one will miss Obama and his running mate.
The rally at the old state capitol gets underway at 1 p.m. The gates open an hour earlier at noon.
The Obama campaign reminded supporters that parking is limited. And they're encouraging people heading to Springfield to carpool.