Kentucky Derby winner Animal Kingdom will not compete as planned in the $10 million Dubai World Cup, trainer Graham Motion said on Monday. Motion said that Animal Kingdom came out of a turf workout on Saturday “sore” in the same leg he injured last year in the Belmont Stakes, his left hind. In a press release, Animal Kingdom’s owner Team Valor International said the colt developed “lameness” in the leg after working five furlongs in 1:04.80 at Palm Meadows on Saturday. Animal Kingdom missed the last half of 2011 after being found with a hairline fracture of the hock following his sixth-place finish in the Belmont. He underwent surgery in late June and returned to training in September. Motion said veterinarians are trying to determine the extent of the injury, and that they don’t know if the problem is related to his injury from last year. “We noticed Sunday morning that he wasn’t 100 percent, that he was sore in the same leg he injured in the Belmont,” said Motion. “We took X-rays and had them examined by Dr. Dean Richardson at New Bolton and he said there appeared to be no change to the original injury, that he’s happy with the surgery site, so at this point we’re just not sure if the problem is related to that injury or is something different. But under the circumstances, obviously we cannot think about shipping him to Dubai now.” Motion said he is in the process of setting up a bone scan for Animal Kingdom to help determine the full extent of the problem. “We should have a better idea in about 48 hours what type of problem we are dealing with,” said Motion on Monday. Team Valor CEO Barry Irwin said he and his partners are disappointed that they cannot take Animal Kingdom to Dubai  for the March 31 World Cup at Meydan Racecourse over about 1 1/4 miles on the Tapeta main track. “This is a crushing blow for our company and our partners as well as our trainer, who has done such a great job getting the horse back to this point,” Irwin said. “If he comes out of this OK, hopefully we can run in the World Cup in 2013.” Said Motion: “Naturally this is a major disappointment. We were all looking forward to racing him in Dubai.” Animal Kingdom, who also won the Grade 3 Spiral at Turfway and finished second in the Preakness last year, registered an impressive allowance victory over the Gulfstream Park turf course last month in his first start since the Belmont. Saturday’s workout was his first since that outing. He was scheduled to have one more work next weekend at Palm Meadows before shipping out to Dubai.[bc_video_id:235347:] Animal Kingdom was expected to go postward among the favorites in the Dubai World Cup along with fellow U.S. invader Game On Dude. Breeders’ Cup Ladies’ Classic and Eclipse Award winner Royal Delta is also expected to represent the U.S. in the race. Other key contenders in the World Cup are expected to include So You Think, a New Zealand bred, who finished sixth in the 2011 Breeders’ Cup Classic, and Japan’s six-time Group 1 winner Smart Falcon. Victoire Pisa led a one-two sweep for Japan in last year’s World Cup. On Sunday, Animal Kingdom’s stablemate Howe Great put himself in this year’s Kentucky Derby picture with his victory in Gulfstream’s Grade 3 Palm Beach Stakes. Howe Great, who is also owned by Team Valor, will attempt to earn himself a spot in the Derby field when he returns next month in the Grade 1 Blue Grass at Keeneland.