Wisconsin Republican congressman Paul Ryan says he might decide as early as this week whether to run for Senate to replace retiring Democratic Sen. Herb Kohl.

A Senate run would force Ryan to give up his chairmanship of the powerful House Budget Committee.

Appearing Sunday on CNN's "State of the Union," Ryan said his family and supporters just started digesting the idea.

Other possible candidates include Wisconsin Attorney General J.B. Van Hollen, former Rep. Mark Neumann, who lost in the Republican gubernatorial primary last year, and a pair of brothers who lead the Wisconsin Legislature and are closely tied to Walker and his anti-union plan -- Scott and Jeff Fitzgerald.

Kohl's surprise retirement creates at least eight open seats that could help determine the balance of power in the Senate.