Update (3:18 p.m.): That was fast. Obama addressed the press a few minutes after The LA Times broke the story. "In the end the pull of the hometown we both love… was too great," the president said. "I plan to continue to seek Bill's advice and counsel in the years to come." POTUS also said of Daley, that "No one in my administration has had to make more important decisions more quickly than Bill."

Original Post: The White House will announce on Monday afternoon that President Obama's chief-of-staff Bill Daley resigned last week, according The Los Angeles Times. Chief of staff and budget director Jack Lew is expected to take over the team. The LA Times's Christi Parsons explains the switch:

The choice of Lew puts a veteran staffer of the White House, Capitol Hill and State Department in a critical position at a difficult time for the president. Obama hopes he can work through tough budget and economic issues with Congress this year despite fierce opposition from Republicans in the GOP-led House. Having a strong team captain who can deal with lawmakers, staffers and business leaders is considered crucial to their strategy.

But aides say Obama had faith in Daley to lead that effort, and that he had not been discussing making any changes prior to last week. Daley’s letter took the president by surprise, said three officials familiar with the personnel discussions that followed.

While the letter January 3 resignation letter was a surprise to the president, the news that Daley is taking a step back is not. Back in October, Daley was already signaling that his return to Chicago was imminent, and then a month later, Obama more or less relinquished Daley of his day-to-day duties in what Parson's calls "a change in the flow chart … keeping Daley in charge but shifting many of the day-to-day operational duties to Pete Rouse." Daley said in his resignation letter, "I have been honored to be a small part of your administration … It is time for me to go back to the city I love."

We're waiting on more details from the White House's official announcement and will update this post when it hits our inbox.