Friesan Fire, the favorite in this year's Kentucky Derby off three consecutive stakes victories in Louisiana, is scheduled to undergo surgery on Friday for injuries discovered this week and will be out for at least several months, according to the colt's owner, Vinery. \nTom Ludt, the general manager of Vinery, said that X-rays had revealed a stress fracture in Friesan Fire's left front leg and a non-displaced chip fracture in the colt's right front fetlock. Friesan Fire was expected to undergo operations on Friday to repair the damage at Rood and Riddle Equine Hospital, just outside of Lexington, Ludt said.\nFriesan Fire finished 18th in the Kentucky Derby after grabbing a quarter early in the race. Following a 10th-place finish in the Preakness Stakes, Friesan Fire was expected to be given the next two months off at Vinery before resuming training, Ludt had said on Monday. \nTrained by Larry Jones, Friesan Fire won the Louisiana Derby in his last start prior to the Derby, and, despite the seven-week layoff, was made the 7-2 favorite at Churchill Downs in a field of 19. He had previously won the Lecomte and Risen Star stakes at Fair Grounds.