Political prognosticator Charlie Cook fired a shot over the bow of Sen. Chris Dodd's (D-Conn.) reelection bid on Thursday.

Cook moved the 2010 Senate race from "Likely Democrat," the second-most safe rating, to "toss up," indicating an increasingly tough reelection battle for Dodd.

Dodd will likely face former Rep. Rob Simmons (R-Conn.) in one of the most closely watched matchups of the midterm election cycle.