WASHINGTON — The secret holding, Barack Obama on Friday readied announcement by text message of his vice presidential running mate from a list suddenly spiced by a dark horse from Texas.

Hillary Rodham Clinton's prospects remained a mystery on a day full of them, although senior aides said the Obama campaign had never requested financial or other records from her.

Three days before the party gathers in Denver to nominate Obama for the fall campaign, several officials said Rep. Chet Edwards, whose district includes President Bush's ranch in Crawford, Texas, had made the roster of potential running mates. Sens. Joe Biden of Delaware and Evan Bayh of Indiana were also in the mix, as were Govs. Tim Kaine of Virginia and Kathleen Sebelius of Kansas — and any unknown others Obama had managed to keep secret despite intense scrutiny.

"It'll be exciting news," Sebelius told reporters in Kansas.

Obama, his secret his own, went to the gym for a morning workout before heading to an office in Chicago to polish the convention acceptance speech he will deliver next Thursday night.

Obama told reporters on Thursday he's already made his choice, and aides have used the prospect of a text-message announcement to try to attract additional supporters by soliciting their cell phone numbers and e-mail addresses.

The Illinois senator has arranged a joint appearance for Saturday with his running mate at the Old State Capitol in Springfield, Ill.

Hundreds of miles to the west, carpenters, electricians, sound stage gurus and others transformed the Pepsi Center in Denver into a made-for-television convention venue.

Tucked away in one corner were thousands of lightweight rolled cardboard handles, meant to allow delegates to wave signs bearing the names of the ticket — once the identity of Obama's running mate was known.

And he wasn't saying.

"Obviously, the most important question is: Is this person ready to be president?" Obama told "The Early Show" on CBS. Second, he said, was: "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, he added: "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.

Among those believed in the running, Biden, Bayh and Edwards fit the mold of running mate with experience in defense or foreign policy — areas in which Obama performs relatively poorly in the polls compared with Republican Sen. John McCain.

Clinton's credentials were forged in the primaries and caucuses where she ran a close second to Obama in the battle for the nomination.

There was no shortages of other speculation, ranging from: GOP Sen. Chuck Hagel of Nebraska, who traveled with Obama to Iraq and Afghanistan; Massachusetts Sen. John Kerry, the 2004 Democratic presidential nominee, or Democratic Sen. Chris Dodd of Connecticut.

Edwards, whom Speaker Nancy Pelosi had touted for running mate, told reporters in Waco, Texas, "I have had interactions with the Obama campaign over the last several months but I will not get into details."

One Democratic official with knowledge of the conversation said Obama told Pelosi recently that she would be pleased with the choice. Other Democratic officials said he was on the short list. All spoke on the condition of anonymity because they were not authorized to discuss Obama's selection process.

Edwards, chairman of the Military Construction and Veterans Affairs Appropriations Subcommittee, is a nine-term moderate Democrat representing the GOP-leaning Texas district. He is well-known in Texas but does not have a national profile.

Among the other potential choices, Biden was at home in Delaware and Bayh attended tennis camp with one of his children. Kaine was with his son at college in Washington. He paused long enough to confide that while his son had signed up for a text message announcement, "I haven't because I don't know how."

Several GOP officials said Friday that McCain had not settled on a running mate — nor offered the job to anyone — although former Massachusetts Gov. Mitt Romney and Minnesota Gov. Tim Pawlenty were under serious consideration.

Officials said the campaign also was preparing for an "unconventional" nominee, an indication that oft-mentioned former Pennsylvania Gov. Tom Ridge, an abortion-rights supporter, or Connecticut Democrat-turned-independent Joe Lieberman still could be in the running. That category also could include non-politicians whom McCain admires, such as Gen. David Petraeus, the top U.S. commander in Iraq.

The GOP convention begins Sept. 1 in St. Paul, Minn.

Associated Press writers David Espo in Denver, Glen Johnson in Boston, Randall Chase in Greenville, Del.; Bob Lewis in Richmond, Va. Scott Lindlaw in San Francisco, Angela K. Brown in Waco, Texas, and Jesse Holland in Washington contributed to this report. Pickler reported from Chicago.