Brad Herold, who shepherded Republican Senate candidate Mike McFadden's surprise endorsement, has stepped down as McFadden's campaign manager.

Herold came from Florida to run McFadden's campaign in September. He will now become a senior adviser to the campaign, McFadden spokesman Tom Erickson said.

"Brad is still a member of the McFadden for Senate team. Our plan has always been to retool the campaign after becoming our party's nominee," Erickson said.

The McFadden shake-up was first reported by the Morning Take e-newsletter.

Erickson said Herold will advise McFadden in his quest to oust Democratic U.S. Sen. Al Franken.

"Brad will still be involved in his new position as a senior adviser to the campaign. We look forward to making an announcement about our new campaign manager in the coming days," he said.