The chief of staff to Sen. Chuck Grassley (R-Iowa) will try to join his boss in the Senate, strategists familiar with his plans confirm. As first reported by the Iowa Republican Web site, David Young plans to quit his job in the Capitol and run for Senate in Iowa.

Sen. Tom Harkin (D) is retiring, and the field of Republicans aiming to replace him could get crowded. 

U.S. Attorney Matt Whitaker is also launching a bid. Iowa state Sen. Joni Ernst and Secretary of State Matt Schultz are both looking at the race. Some high-profile Republicans, including conservative Rep. Steve King, have opted out of the race, leaving the field open.

On Young's side will be Fred Davis, the Republican admaker behind several buzzy spots -- including Delaware Senate candidate Christine O'Donnell's "I'm not a witch ad" in 2010. Davis knows Young already because Grassley is one of his clients. Sara Taylor Fagen, who served as George W. Bush's political director, is supporting Young and plans to offer him strategic counsel.

"He would certainly bring a lot of experience to the job, but making the leap from staff to member is pretty difficult -- it doesn't happen very often," said one Iowa Republican. "One key will be the extent to which Sen. Grassley decides to weigh in and help him."

On the Democratic side, Rep. Bruce Braley is the presumptive nominee.