Sort of. Spokesman David James did not actually acknowledge Jeff Atwater's potential candidacy, and instead implied that the press is manufacturing doubts about the Mack campaign in order to damage the Republican frontrunner for the U.S. Senate nomination:

"Connie Mack has sent Bill Nelson and his liberal allies, including those in the press, into panic mode and it won't work. Republicans know that  conservative Connie Mack will defeat liberal Bill Nelson and Mitt Romney will defeat Nelson's chief ally Barack Obama, regardless of what the left wing media wants."

No comment from the George LeMieux campaign.