Sauerberg is a family physician and political newcomer from the Chicago suburb of Western Springs. He's argued that Durbin is beatable in 2008, saying his own candidacy will offer fresh ideas.
No major officeholder has stepped forward to try to unseat Durbin, who's the second-highest ranking Democrat in the U.S. Senate.
Republicans have been looking for prospective nominees who could help fund their own campaigns.
Durbin had more than $6 million in his campaign fund as of last month and says he's prepared to raise millions more if