The field for Saturday's $750,000 Stephen Foster Handicap (gr. I) gained Congaree, but it lost the Niall O' Callaghan-trained Hail the Chief when he was withdrawn from the race because of injury. O'Callaghan's bid for a second consecutive Stephen Foster victory ended when he revealed that the Hawthorne Gold Cup (gr. II) winner suffered a minor ankle injury during a recent workout at Churchill Downs. Hail the Chief breezed five furlongs in :59.40 over a fast track last Friday, and the Irish-born trainer said the problem surfaced after that move. O'Callaghan said Hail The Chief sprained his left front ankle."We decided to give him 30 days. It's not a serious injury. You could give consideration to running him on Saturday, but I've decided not to because I feel that it's too much of a chance to take."In other Stephen Foster developments, Unshaded worked five furlongs handily in :59.40 over a fast track under exercise rider Tracy Wilkes. The work was the second fastest recorded at that distance. Parade Leader breezed four furlongs in :49.40 under exercise rider Fernando Mera. Both works were on Tuesday.The Stephen Foster will be the just the second start of the year for Unshaded, who won the Travers (gr. I) and Coolmore Lexington (gr. II) at three. He finished second to X Country, a subsequent stakes winner at Mountaineer Park, in a one-mile allowance at Churchill Downs on May 18.