White House chief of staff Jack Lew is expected to be nominated to replace Treasury Secretary Tim Geithner, likely by the end of this week, two sources close to the process told Fox News.

"It is all but a done deal," one of the sources said, adding that it would take something "extraordinary" to pop up in the next couple of days to derail that decision.

Geithner has said for well over a year that he would like to leave the administration and spend more time with his family after a grueling time playing key roles throughout the economic and fiscal unease of recent years. His tenure at the Treasury followed previous service as head of the New York branch of the Federal Reserve.

Lew has become an Obama favorite through several top posts because of his sharp knowledge of the federal budget and no-drama style.

Picking Lew is a sign the president knows his next Treasury secretary will be smack in the middle of a series of budget battles, starting with the debt ceiling fight that will be brewing during the expected confirmation process.

A red flag is that during the last debt ceiling fight, in the summer of 2011, Lew served as White House budget director and clashed repeatedly with Republicans, who may want to get a pound of flesh in confirmation hearings.

In fact, advisers to the president say Lew deliberately kept a low profile during the recent fiscal cliff talks so as not to enflame those tensions on the eve of the expected announcement of his nomination for Treasury.

Ed Henry currently serves as Fox News Channel's (FNC) chief White House correspondent. He joined the network in June 2011.