There was sad news out of the Palm Meadows training Center – 2011 Kentucky Derby winner Animal Kingdom will not make his next start on March 31 in the $10 million Dubai World Cup. Horse racing is once again showing its highs and its lows.

For the connections of champion Animal Kingdom, Sunday was one of those times that tested their resolve. Team Valor’s Animal Kingdom emerged from his recent workout with an injury to his left hind leg.

Animal Kingdom breezed 5 furlongs over the turf at Palm Meadows Training Center on Saturday. The following morning, trainer Graham Motion said Animal Kingdom was lame in his left hind leg. Surgery sidelined Animal Kingdom after the Belmont Stakes when he had surgery to repair a hairline fracture of his left hock. Motion said that the nature and severity of his current injury is still being determined.

“We really don’t know what it is right now,” Motion said. “There is nothing obvious apart from the fact that this is the same leg that he injured before. Obviously when you have an injury like that, arthritic changes come with that but … the site (of the previous injury) looks very good. More than likely he’ll go for a bone scan in the next 48 hours to figure out what is going on. It could be something completely different, it just happens to be on the same leg. We don’t really know at this point.”

Adding to the dismay surrounding Animal Kingdom’s injury is how well he seemed to recover from his previous setback.

Since Animal Kingdom had won the Vinery Racing Spiral Stakes on the Polytrack at Turfway Park last March, he was considered a strong contender for the Dubai World Cup, which is also contested over a synthetic surface.

“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,” Barry Irwin, CEO of Team Valor, said in a statement. “If he comes out of this okay, hopefully we can run in the World Cup in 2013.”

Animal Kingdom’s injury cast a shadow over what should have been a great weekend for Motion, Velazquez and Team Valor. Hours after the reigning 3-year-old champion male was found to be lame, his stablemate Howe Great — also owned by Team Valor and ridden by Velazquez — defeated Dullahan in the Palm Beach Stakes at Gulfstream Park.

“To go from the morning watching (Animal Kingdom) walking in the barns to saddling that horse (Howe Great) in the afternoon, that’s about as extreme as you can get,” Motion said. “I think to come this far and to get this close and have the prep go so well, it’s pretty tough.”