McCain source: VP announcement not settled

(CNN) -- Sen. John McCain has not settled on a running mate and the timing of any announcement has not been determined, a senior McCain source told CNN.

That appears to differ from a Washington Post report Friday that the Arizona senator plans to announce his vice presidential choice at some point before the Olympic Games in China that kick off August 8.

But the McCain source told CNN discussions about a running mate are ongoing and McCain has given no indication of a decision. Moreover, McCain is just as likely to announce his choice at the end of August as he is in the first part of the month.

Asked to comment on the report later Friday, McCain told CNN's Wolf Blitzer that he couldn't.

"I can't comment on the process that we're going through. I apologize for being so obtuse," McCain said. "When we start commenting, you really get on a slippery slope and sometimes that's unfair to the people that are under consideration."

But earlier this week, top McCain adviser Charlie Black told CNN the campaign has done enough vetting of vice presidential prospects, for McCain to make a decision whenever he wants.

Meanwhile, another day, another round of buzz surrounding a potential vice presidential candidate.

This time it's former Bush administration official and former Ohio Rep. Rob Portman, who made an unscheduled appearance aboard McCain's Straight Talk Express Thursday afternoon.

McCain and Portman headed to Columbus, Ohio, Thursday where the Arizona senator participated in a town hall event with biking legend Lance Armstrong. Watch Armstrong discuss the McCain event »

Portman, who served as Director of the Office of Management and Budget from 2006-07, has long been considered a top pick for vice president.

In addition to his economic credentials -- something many political observers believe McCain's ticket desperately needs -- Portman remains a popular figure in his home state of Ohio, the perennial presidential battleground once again expected to play a key role this cycle. CNN's Political Market: Portman's VP stock on the rise

Portman represented Ohio's conservative 2nd district for 12 years, and could help shore up conservative support and working class voters there. Obama lost to Sen. Hillary Clinton in Ohio by nearly 10 points in the Democratic primary -- largely due to a lack of support from working class Democrats -- though recent polls show the Illinois senator now holds a slight lead over McCain.

But Republicans may be wary of putting a former Bush administration official on the ticket, and he remains relatively unknown on the national scene.

And there's always the question of whether Portman is interested in the job. The former congressman appeared to suggest last month he was not.

"Well, you know, I'm happy to be home," he told CNN's Peter Hamby. "I commuted between Washington and Ohio, where we are now, for 15 years and about nine months, so I made the decision to come home and it's been great. I've got three teenagers, so I'm not looking for a way back to Washington right now."

"I love public service," he added. "I want to help him. I think he's the right person to lead the country at this critical time, but I'm not interested in going back to D.C. right now."

Meanwhile, another prospect, Louisiana Gov. Bobby Jindal, said Wednesday that there is no way he will fill the bottom half of the GOP presidential ticket.

"I'm not going to be the vice presidential nominee or vice president," Jindal told Fox News. "I'm going to help Sen. McCain get elected [president] as governor of Louisiana."

"Let me be clear: I have said in every private and public conversation, I've got the job that I want," Jindal said.

It's not uncommon for those being considered for a slot on the presidential ticket to deny interest in the position, but Jindal's blanket statement is notable, especially in light of the fact that he is widely considered to be on McCain's shortlist.

It also came as the two men were scheduled to sit down at a private meeting the McCain campaign refused to discuss. On Wednesday afternoon, the meeting was postponed due to weather.

Speculation swirled around Jindal this summer when he was one of a handful of politicians McCain invited to his Sedona, Arizona, ranch. The long weekend was described as purely social, though former Massachusetts Gov. Mitt Romney and Florida Gov. Charlie Crist were also in attendance.

Jindal is considered a rising star of sorts in the Republican Party and has been lauded by several conservatives wary of McCain, including talk-radio host Rush Limbaugh.

But the decision would undercut one of the Arizona senator's chief arguments against Obama: his relative lack of experience. Jindal is nearly 10 years younger than Obama.

Meanwhile, a Republican source who attended a small private meeting with John McCain in New Hampshire told said the GOP candidate dropped a serious hint about his potential running mate.

The source said "out of the blue," McCain told the gathering Tuesday that he thinks they are "really going to like" Minnesota Gov. Tim Pawlenty.

This source said McCain may have been talking about Pawlenty because the meeting was with New Hampshire GOP delegates, and the Republican convention is in Pawlenty's state.

Pawlenty is a longtime supporter of McCain. He's from a swing state with considerable support across the Republican Party, including evangelicals, and has always been thought by Republican strategists to be on McCain's short list.

Veepstakes speculation swung into high gear Monday, when sources in McCain's campaign confirmed there were discussions at high levels about naming a running mate this week.

Sources in the McCain campaign confirmed to CNN's Dana Bash and Gloria Borger that there have been recent discussions high in the campaign about possibly naming a running mate this week.

One source said "no decision has been made" by the candidate. Another said that some within the campaign are arguing to hold off until Obama has named his decision "so there is an opportunity to counter-program."

CNN's Ed Hornick, Dana Bash, Peter Hamby and Alexander Mooney contributed to this report.

All About Bobby Jindal • Tim Pawlenty • Rob Portman