COLUMBIA, S.C. (AP) -- Republican presidential contender Michele Bachmann lost her campaign chief Monday, along with his close deputy, in a campaign shake-up that the Minnesota congresswoman's aides sought to downplay.
Citing health reasons, veteran GOP strategist Ed Rollins stepped down as campaign manager. Bachmann said one of her strategists would take over on an interim basis as Rollins moves to a senior adviser role.
"In less than 50 days and with fewer resources than other campaigns, Ed was the architect that led our campaign to a historic victory in Iowa," Bachmann said in a statement released late Monday, pointing to her win in the Ames Straw Poll last month. "I am grateful for his guidance and leadership, and fortunate to retain his valuable advice even though his health no longer permits him to oversee the day-to-day operations of the campaign."
Speaking to CNN, where he was a contributor before the Bachmann campaign, the 68-year-old Rollins said the front-runners were now former Massachusetts Gov. Mitt Romney and Texas Gov. Rick Perry. He said Perry's late entry into the race slowed Bachmann's buzz and fundraising.
"I think legitimately it's a Romney-Perry race," he said. "I think she's the third candidate at this point in time - which is way different and better than we'd thought when we started this thing - and she's very much in this thing."
Rollins, who suffered a stroke a year and a half ago, said his plan had been to put together a team and get through the Iowa straw poll and then make a transition.
"I have great affection for her. I'll do everything I can to help her. It's still very much the team I put in place. I just don't have the endurance to go 12-, 14-hour days seven days a week anymore," he said.
Rollins' departure as campaign chief was first reported by Politico.
His deputy, David Polyansky, who worked with him when they ran former Arkansas Gov. Mike Huckabee's presidential bid in 2008, also planned to step aside, Rollins told CNN.
"David and I have been a team for a long time," he said. "It's just a good time to make a change."
Bachmann, who won election to Congress in 2006 and was a leader of tea partyers on Capitol Hill, had been making great strides in her presidential bid. Her strong showing in debates and forums lent her credibility, and her win in the key early test vote in Ames, Iowa, showed she was serious about building a campaign organization.
Then Perry, a tea party favorite who could overshadow her, entered the race the same day Bachmann won the straw poll, slowing her momentum.
"It makes it harder. But at the end of the day, he's got to prove himself in a very tough arena, in debates and all the rest of it," Rollins said.
Campaign strategist Keith Nahigian was assuming the role of campaign manager on an interim basis. Prior to the Bachmann campaign, he was a government consultant at the Health and Human Services Department to the Homeland Security Department, as well as to the National Security Council.
"Keith has played a vital role in the success we have had to date and I'm confident he can lead us to a strong finish in Iowa, New Hampshire, South Carolina and across the country," Bachmann said in her statement.
Bachmann is no stranger to top-level turnover. She has experienced frequent staff changes in her congressional office since 2007, and not just in low-level positions that typically see a parade of younger, inexperienced staffers bouncing from one office to the next. She has had six chiefs of staff in four years, five press secretaries, five legislative directors and three communications directors.
Some former staffers have complained about Bachmann's style. They have said questioning her decisions draws suspicions of disloyalty and noted that she insisted on being involved in even the smallest details.
Bachmann has discounted her congressional staff churning as "growing pains" in an office that "moves at a fast rate of speed," and she stresses that many left for more influential jobs elsewhere.
Associated Press writers Brian Bakst in St. Paul, Minn., and Kasie Hunt in Elk Rapids, Mich., contributed to this report.