Speculation swirled Wednesday that US President Barack Obama may shake-up his crisis-scarred staff, as top political enforcer Rahm Emanuel mulled a run for Chicago mayor.

Emanuel, the White House chief of staff and a legendary political bruiser, has made no secret that running his native Windy City would be his dream job.

So Washington's political jungle, already on edge over a possible Democratic wipe-out in upcoming legislative polls, was set buzzing Tuesday when Mayor Richard Daley suddenly announced he would not run for a seventh term in 2011.

Careful statements by Emanuel and top White House aides did little to scotch speculation he would leave, in a move that could allow Obama to overhaul his braintrust and make a fresh start after November's election.

David Axelrod, another top Obama advisor who earned his spurs, like Emanuel, in roughhouse Chicago politics, said Emanuel would decide in "due time."

"For the same reason that Rahm would be an extraordinary candidate for mayor, he's extraordinarily valuable to the president," Axelrod told NBC.

"But no one is indispensable. And if that's the direction he decides to go, there are many here who are ready to fill in the breach."

Axelrod was among many White House staffers who appeared stunned late Tuesday when Daley, dubbed "mayor for life" and heir to a Chicago political dynasty, said it was time to go, at the age of 68.

Emanuel must now calculate whether he wants to leave the pinnacle of power in Washington to return home, and assess his chances of victory.

Though well-known in Chicago, and possessed of sharp fundraising skills, he has also been out of the city for years, on-and-off, and would have to rebuild a local power base.

Should he run in February's election, he would be expected to send some kind of signal fairly quickly.

A flurry of names who could replace Emanuel were already surfacing in the Washington rumor mill on Wednesday.

If Obama chose a low profile member of his inner circle, pundits said he could pick Tom Donilon, a deputy national security advisor, or another foreign policy hand, Denis McDonough.

Should he want to send a message that he has heard a message of voters after a possible Democratic defeat in November, he could try to persuade someone like Bill Clinton's ex-chief of staff John Podesta to sign up.

Other possible picks include former Senate majority leader Tom Daschle, a veteran of Washington power politics. But Daschle may be a controversial choice as he quit as Obama's nominee for health czar because of tax questions.

Obama's close friend Valerie Jarrett, already a senior White House aide is also seen as a possible choice.

Emanuel, a veteran of the Clinton administration was seen by some as a surprising pick by Obama, as he glorified in the kind of political brawling that the president spent much of his 2008 election campaign running against.

But he was also close to the Democratic hierachy on Capitol Hill, contacts he used to help Obama pass historic legislation including a huge stimulus plan, health care reform and and an overhaul of finance regulation.

Critics however complained the administration handed too much control over the bills to Democrats in Congress, exposing Obama to damaging claims he was in thrall to "liberals" left of the political mainstream.

Emanuel has also been under fire for his reported comment that "No crisis should go to waste" -- which prompted Republicans to complain he exploited the economic meltdown to pass a liberal wishlist of bills.

Others are dismayed that after a pitch-perfect presidential campaign, Obama's team has failed to dominate the political messaging of government and suggest he has lost touch with everyday Americans.

Emanuel, 50, an observant Jew, has also been a go-between between Obama, who some critics accuse of being anti-Israel, and the Jewish community and even the Israeli government as Middle East peace talks resume.

Should he leave, he will also be missed by journalists whom he has supplied a steady stream of political lore.

Last year, the White House was forced to deny claims that a naked Emanuel berated one congressman for perceived political cowardice in a communal shower in Capitol Hill.

The lawmaker, Eric Massa, stepped down after a harassment scandal, but not before he had branded Emanuel as "the son of the devil's spawn" who would sell his mother for a vote.

Obama once joked that the notoriously salty Emanuel's loss of a middle finger in a childhood meat-slicing accident "rendered him practically mute."