Arkansas Derby winner Sir Cherokee was scratched from Saturday's Kentucky Derby (gr. I) Friday morning after it was revealed he had suffered an injury in the last few days.Trainer Mike Tomlinson informed the racing office that the Arkansas Derby (gr. II) winner had a small fracture in the P1 bone in the right rear ankle. On Tuesday, Sir Cherokee was vanned to Churchill Downs from the nearby Trackside Training Center and breezed five furlongs in 1:00 3/5."The timing of it is horrendous," an emotional Tomlinson said during a press conference on the backside at Churchill. " 'Lady luck' didn't shine on us. It's tough to get your foot in the door, and then we get it squeezed. This is not a game for guys in short pants. These are the highs and lows of the game and we'll be back."His work went well and he came out nicely. We were pleased. Yesterday (Thursday) he jogged and after the jog he wasn't himself. He was not lame but he was not 100%. After his bath he was slightly off and he was sore."Tomlinson said the good news is that the injury is not career-ending. "The upside is he will be back. The prognosis is 100% that he will be healthy and sound. He will get two weeks of stall rest followed by 60-90 days of hand walking. He may be able toe resume training in 90-120 days."By Cherokee Run and out of the Last Tycoon mare La Cucina, Sir Cherokee is a homebred racing for Ken Jones' Domino Stud. Sir Cherokee was 15-1 on the morning line. He was to be the first Derby mount ever for jockey Terry Thompson.Since Sir Cherokee would have started from the 3 post, Supah Blitz and Brancusi, who drew the 1 and 2 post positions, will move out one slot in the starting gate.