Marco Rubio, the insurgent conservative candidate in the Florida Republican Senate primary, seems to be having some trouble building up momentum -- and now comes a new wave of staff shake-ups.

Rubio's campaign manager is now leaving, and his chief fundraiser is also out of the picture. "At this point, Speaker Rubio believes it is necessary to click the reset button in certain areas of the campaign," the campaign said.

Polls have Rubio far behind moderate Gov. Charlie Crist, who has also built up an overwhelming fundraising advantage. Rubio has also had to shoot down reports that he might drop out of the race and run for something else.