Fifty Stars, unraced since suffering a right front ankle chip while finishing ninth in last year's Kentucky Derby (gr. I), has been sent back to the sidelines due to a broken splint bone in the same leg. The injury occurred during a Tuesday morning workout in preparation for the New Orleans Handicap (gr. II), according to trainer Steve Asmussen. X-rays have been sent to a surgeon and a decision on treatment is expected in a few days.James Cassels and Bob Zollars' Fifty Stars (Quiet American -- My Bubbling Belle, by Tsunami Slew) has won three of nine career starts, including the Louisiana Derby (gr. II). He followed the Louisiana Derby victory with a second-place finish in the Lone Star Derby prior to his Kentucky Derby run.Fifty Stars' previous injury required surgery and the colt had been working steadily toward a return to the races since the fall.