Rahm Emanuel (Creative Commons)

Pete Rouse, a senior adviser to President Barack Obama, is "no surprise" as the next in line.

The "low-key aide is widely respected in Washington" and served as chief of staff for Sen. Tom Daschle, D-SD, when he was Senate Minority Leader and Majority Leader. He earned the nickname "the 101st senator" during that time and has been referred to as "an understated" politico with "30-odd years of Capitol Hill experience."

He was hired by Obama to run his senate office in 2004 after Daschle lost. Obama and Rouse are reportedly "extraordinarily close."

Rouse received high praise from White House press secretary Robert Gibbs on Thursday: "The type of trust the president and others in the administration have in Pete is enormous."

It is unclear whether Rouse will serve as interim chief of staff or take over the position permanently.

When Chicago Mayor Richard M. Daley announced his retirement in early September, word spread that Emanuel was eyeing a run. Officials close to the situation are saying the official announcement of his resignation will be made on Friday.

Emanuel has long been vocal about his desire to hold office in Chicago.

"One day I would like to run for mayor of the city of Chicago...That's always been an aspiration of mine, even when I was in the House of Representatives," he said in April.

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