But the White House wasn't ready to confirm or deny the source-based report.
Carney then briefly outlined some of Lew's career highlights in Washington over the past quarter century, noting he "continues to be an extremely valuable adviser to the president" and is "an exceptional, exceptional public servant."
Asked if Lew has been working on his signature -- the treasury secretary's names appear on U.S. currency -- Carney responded, "Not that I'm aware of."
Carney swept aside a question attempting to link Lew to the federal loan given to now-bankrupt solar tech company Solyndra and Lew's previous role as chief operating officer of a Citigroup unit clouded by the burst in the housing market.
He said Lew's record "has and continues to be stellar" and said he is "that rare person in Washington who has been here for years who has done some very hard things and brokered some serious bipartisan agreements and done it in a way that has earned the admiration of almost everybody he's worked with; so certainly, the presidents that he has served."
Lew has been a central behind-the-scenes figure in the Clinton and Obama White Houses as head of the Office of Budget and Management, Politico noted Wednesday.
If confirmed by the Senate, Lew would break the mold of recent treasury chiefs, less a financial market expert with broad contacts in the business world than a loyal Democratic lieutenant and budget authority, The Wall Street Journal said Wednesday.
The position comes open as Washington, recovering from the exhaustion of "fiscal cliff" negotiations, readies itself for budget fights over the nation's debt limit, sequestration cuts and a measure to continue funding the government, the Washington newspaper The Hill reported.
The Hill said information on the nomination came from "a Democratic official familiar with the matter."
Republicans view Lew as capable but rigid, after contending with him during budget battles going back to the 1990s, and some Republicans said he was unwilling to offer concessions to cut a debt ceiling deal in 2011, the Journal said.