U.S. Ambassador to China Jon Huntsman has tendered his resignation, opening the door to a possible run for the presidency.

Huntsman offered his resignation on Monday, according to a senior administration official. The resignation is effective in April.

The decision was widely expected. Just over a week ago, President Obama himself was asked about the possibility of Huntsman running for the GOP nomination for president in 2012.

To laughter from reporters, Obama replied during a press conference with Chinese President Hu Jintao that he thought Huntsman would do well with whatever pursuits he chose in the future.

“I’m sure that him having worked so well with me will be a great asset in any Republican primary,” Obama joked at the time.

Huntsman is a former governor of Utah who gave up that position in 2009 to become U.S. ambassador to China. When Huntsman took the job, the White House was seen as taking a potentially tough opponent out of the field for 2012, and it remains unclear how Huntsman would explain his work for the administration to conservative GOP primary voters.

White House press secretary Robert Gibbs said Monday that Huntsman had told several people in the White House that he planned to leave the administration during the first part of this year.

“The president, and I think the American people, expect that somebody that holds the post of ambassador from the United States to China would dedicate their full energy and time to that position,” Gibbs continued. “And we believe that Ambassador Huntsman believes that as well.”

Huntsman hinted at a run for the White House in an interview with Newsweek published earlier this month.

"You know, I'm really focused on what we're doing in our current position," Huntsman said. "But we won't do this forever, and I think we may have one final run left in our bones." 

News of Huntsman's expected departure as ambassador to China was first reported by Politico

Back in the spring of 2009, it was Obama's campaign manager, David Plouffe, who identified Huntsman as one potential GOP contender who makes him a "wee bit queasy." The president named Huntsman ambassador to China later that same month. 

Late last week, GOP operative Susie Wiles signed on as executive director of what's expected to be Huntsman's political action committee. The former governor also has a core of top advisers already laying the groundwork for a possible run.

Before January's state dinner at the White House, Huntsman was asked if he was considering a run in 2012. He answered, "We're loyal to our country and our president."

The core of Republican strategists who have started to pave the way for a potential Huntsman bid see a big opening for the former governor in the current field of rumored hopefuls, despite the conventional wisdom that suggests he's too centrist to make it through a primary.

Should he run, Huntsman will pitch his extensive foreign policy credentials, which are easily the deepest among the current GOP field. Huntsman backers are also pushing the notion that his ties to President Obama are more easily explained away than are former Massachusetts Gov. Mitt Romney's healthcare woes.

Said one GOP strategist, earlier Monday, who's aligned with the pro-Huntsman crowd: "He was a hugely successful and popular governor, with a solid record. So, maybe he's similar to Romney in some sense, but he doesn't have an Obama-like healthcare plan to explain."

Huntsman also has a strong electability argument to boast, given a fairly centrist record that will appeal to independents in a general election. Still, the current GOP primary landscape is undoubtedly a hurdle thanks to those more moderate positions on immigration and gay rights.

"The fact that he's worked for President Obama is simply an anvil around his neck," said one GOP strategist. "So that's the first five seconds of any [campaign] ad. The next 25 seconds is everything else [in his record]."

Another take from a strategist who worked on Romney's 2008 campaign — the former Massachusetts governor should welcome a Huntsman candidacy, "because it moves him further away from Obama."

"It's one thing to have to explain away a healthcare plan," said the strategist, rejecting the argument that Huntsman can overcome his connection to the president. "I just don't see how you explain [to Republican primary voters] working for Obama."

This story was updated at 7:03 p.m.