Ben Carson has plans for a staff shake-up -- soon.

The retired neurosurgeon, who for a time this fall appeared to be a viable candidate for the GOP presidential nomination, is preparing to reorganize his campaign amid tumbling poll numbers and underwhelming debate performances.

"Everything. Everything is on the table," Carson said of the potential changes in interviews with the Associated Press and the Washington Post on Wednesday. "Every single thing is on the table. I'm looking carefully."

Carson, whose campaign has raised large sums but spent money almost as quickly as it has come in, told the Post he wanted "to see more efficiency in terms of the way money is utilized.”

A request for comment from Barry Bennett, Carson's current campaign manager, was not immediately returned.

With the Iowa caucuses just a little more than five weeks away, a staff shake-up could be too late for a struggling campaign to gain traction.

In recent weeks, Carson's campaign has been hit with questions about his biography and his comments about Muslims and Syrian refugees. He has often blamed the media for, in his view, not accurately reporting his statements.

His debate performances, in which he has sometimes struggled to show a basic understanding of foreign and domestic issues, have not helped.

While on the trail in early primary states, Carson speaks at length about his Christian faith, which has given him support of some evangelical Christian voters, particularly in Iowa. Yet that support has declined, with Texas Sen. Ted Cruz picking up many former Carson supporters, polls indicate.

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FOR THE RECORD

Dec. 23, 2:40 p.m.: A headline on an earlier version of this post said Bernie Sanders plans a staff shake-up. It is Ben Carson who is considering staff changes. ------------