Aaron Cook was added Tuesday to the Colorado Rockies' roster for the World Series, and he'll start Game 4 at home against Boston. Cook, who was the Rockies' opening-day starter, hasn't pitched in a major league game since Aug. 10 because of a strained muscle in his side. Cook pitched in a simulated game Saturday at Coors Field while the Rockies waited through a record eight-day layoff for the World Series, proving he was healthy and ready to return to the rotation.