LOUISVILLE, Ky. -- Fulleffort, winner of the Grade 3 Jeff Ruby Steaks who appeared to be training superbly for his first start on dirt in Saturday’s Kentucky Derby at Churchill Downs, will be scratched from the race due to a chip in his left hind ankle, trainer Brad Cox said Thursday.  His defection moves Ocelli into the field.  “Fulleffort had some pressure in his left hind ankle this morning. We took X-rays. He had a chip and he was off, so obviously he will not be running on Saturday,” Cox said.  Cox said Fulleffort will have surgery to remove the chip and be aimed at a campaign in the second half of the year.  :: Get DRF Kentucky Oaks & Derby Clocker Reports by Mike Welsch and the DRF Clocker Team “Don’t want to put the cart before the horse here, but when he comes back, if he trains good, we’ll try the dirt,” Cox said. “Unfortunate for the St. Elias team and the Starlight Racing team. The horse accomplished a tremendous amount in the last eight or nine months and I was looking forward to see what he could do on the dirt.”  Fulleffort, a son of Liam’s Map, had won twice on turf as a 2-year-old. At 3, he took the synthetic route to the Triple Crown, finishing second in both the Leonatus Stakes and John Battaglia Stakes before winning the Jeff Ruby.  Cox still has two Kentucky Derby contenders in Further Ado and Commandment, both Grade 1 stakes winners.  Fulleffort is the second defection since the Kentucky Derby was drawn last Saturday. On Wednesday, trainer Mark Casse announced the scratch of Silent Tactic due to a bruised foot.  Golden Tempo, who was dealing with cracked heels earlier in the week and who jogged Tuesday and Wednesday, did gallop on Thursday morning and it appears he will be fine to run in the race.  Fulleffort, who was to be ridden by Tyler Gaffalione, was to break from post 20.  That post will now be occupied by Ocelli, who is a maiden after six starts, including a third-place finish in the Wood Memorial.  “It’s a tough task, but we think this horse can compete with these other horses,” trainer Whit Beckman said. :: Want to learn more about handicapping and wagering? Check out DRF's Handicapping 101 and Wagering 101 pages.