Doug Mills/The New York Times

President Obama will give his chief of staff, Rahm Emanuel, a send-off Friday as Mr. Emanuel officially announces his departure from the West Wing to run for mayor of Chicago, officials familiar with the decision said.

The White House press secretary, Robert Gibbs, at his daily briefing on Thursday afternoon said that the president would give two personnel announcements on Friday morning from the East Room of the White House. Mr. Gibbs, admitting that he was being purposely “oblique,” would not confirm whether the announcements would concern Mr. Emanuel.

Pete Souza/The White House

The two officials, who declined to be named in advance of the official announcement, confirmed that Mr. Obama planned to name Pete Rouse, a senior adviser, to replace Mr. Emanuel. Mr. Rouse has been at the president’s side since Mr. Obama arrived in Washington nearly six years ago as a senator, serving as his chief of staff.

Mr. Rouse has publicly expressed reservations about taking the chief of staff job for an extended period, but he has apparently agreed to do the job – for now.

Mr. Rouse has a low profile outside the White House and across Washington, but he is extraordinarily close to the president and is respected inside the West Wing and on Capitol Hill, where he was known as the “101st Senator” in his role as an adviser to Senator Tom Daschle of South Dakota, then the Democratic leader.

When Mr. Daschle was defeated in 2004, Mr. Obama hired Mr. Rouse to run his Senate office, a decision that was central to Mr. Obama’s abrupt political rise.

Mr. Emanuel, who has been an outsized presence in the White House since Mr. Obama’s first days, has continued to hold his regular 7:30 a.m. strategy meetings with top White House officials even as he has spent time huddling with political advisers to plan a mayoral run.

He is expected to return to Chicago quickly to begin his campaign there. He has canceled events in Washington – including an event on governing at the National Cathedral next week.

And he also has a new cellphone – with a 312 area code.