Ben Carson speaks at his home in Upperco, Md., in December 2015. Two of Carson’s top paid advisers are leaving the campaign one month before Iowa’s leadoff caucuses. (Photo: Andrew Harnik/AP)

The year 2016 is already off to a rough start for Ben Carson, with two of the Republican presidential candidate’s top aides calling it quits before Jan. 1.

The Hill reported Thursday that Carson’s campaign manager, Barry Bennett, and communications director, Doug Watts, had both notified the retired neurosurgeon of their resignations, “effective immediately.”

“We respect the candidate and we have enjoyed helping him go from far back in the field to top-tier status,” Watts said in a statement to The Hill. “Having just announced raising $23 million for the fourth quarter, more than any other Republican candidate, and passing 1 million contributions and over 600,000 unique donors since March, we are proud of our efforts for Dr. Carson and we wish him and his campaign the best of luck.”

Ben Carson for President campaign communications director Doug Watts, left, and campaign manager Barry Bennett. (Photos: Cliff Owen/AP)

This isn’t the first dramatic exodus from the Carson camp. In June, four senior staffers had already quit the campaign within a month of its launch.

Carson himself had prompted speculation about potential staffing changes in recent weeks, but with the Iowa caucuses just one month away, now hardly seems like the best time for such a shakeup. Especially since questions about Carson’s personal history and his foreign-policy chops appear to have caused a recent drop in his poll numbers.