Virginia Gov. Tim Kaine and Sen. Evan Bayh of Indiana are out. Could Sen. Joe Biden of Delaware be in?

Sources told FOX News that Kaine had been informed he was out of the running for Barack Obama's vice presidential pick, and the Associated Press cited a source who said Bayh had been informed of the same. As for Biden's position as the leading contender, the truth might not be told until Saturday afternoon.

Obama plans to notify the country of his vice presidential pick Saturday -- possibly sometime in the morning -- before the candidate and his chosen appear at a 2 p.m. campaign event in Illinois, FOX News learned Friday night.

The news did little to quell the frenzied speculation about who will be standing on that stage with Obama, but it established a clearer time frame for the announcement after days of frustrated anticipation.

Obama's campaign had invited supporters to sign up for text messages and e-mails notifying them when the announcement was made, and senior campaign officials told FOX the messages will be timed to be received when the nation is awake.

Obama’s campaign has managed to keep a tight veil of secrecy over the decision as media and delegates start traveling to Denver for a four-day extravaganza that will end with an acceptance speech by the first black presidential nominee of a major party.

Journalists, meanwhile, have staked out all the top potential picks for any indications that they may be the one.

The Associated Press reports that several Obama associates have said they believe Biden is Obama's choice, though they haven't been told directly.

If he is the pick, Biden might have some explaining to do. He told FOX News' Alan Colmes on Aug. 10, 2007, that he didn't want the job.

"I am not running for vice president," Biden said at a time he still was a candidate for president. "I would not accept it if anyone offered it to me. The fact of the matter is I would much prefer to stay as the chairman of the foreign relations committee than vice president."

Gov. Kathleen Sebelius of Kansas is still a possibility. And a new name — Texas Democratic Rep. Chet Edwards — entered Friday into the buzz about potential short-listers.

Bayh was the subject of additional speculation Friday evening when reports surfaced that a Kansas company had printed materials touting "Obama-Bayh 2008," though it isn't clear what the rumored materials were for.

Obama, keeping his decision to himself, went to the gym for a morning workout Friday before heading to an office in Chicago to polish the acceptance speech he will deliver next Thursday night.

Asked about his choice, Obama told CBS in an interview that aired Friday morning that the person he vets must be prepared to be president.

"Obviously, the most important question is: Is this person ready to be president?" he said. "The second most important question from my perspective is, can this person help me govern? Are they going to be an effective partner in creating the kind of economic opportunity here at home and guiding us through some dangerous waters internationally?

"And, the third criteria for me, I think, was independence. I want somebody who is going to be able to challenge my thinking and not simply be a yes person when it comes to policymaking."

Obviously, he didn't take that opportunity to name who he thinks fits the bill.

FOX News' Major Garrett contributed to this report.