Dublin, winner of the Grade 1 Hopeful in 2009, suffered a fractured sesamoid in his right foreleg and has been retired from racing, trainer D. Wayne Lukas said Wednesday.\r\nDublin returned from a 14-month layoff last Saturday at Churchill Downs, where he finished sixth in a second-level allowance race. Lukas said the injury was detected back at the barn.\r\n&ldquo;We really were expecting that he&rsquo;d have a hell of a summer,&rdquo; Lukas said. &ldquo;He had five or six bullet works, and we were getting him ready for Saratoga and the fall. We thought we were going to see his potential come full circle.&rdquo;\r\nIn the summer of 2009, as a 2-year-old, Dublin won a maiden race by 3 1/4 lengths and the Hopeful by two lengths, both at Saratoga. He ended his 2-year-old season with losses in the Champagne at Belmont and Iroquois at Churchill.\r\nAt 3, Dublin placed in the Southwest, Rebel, and Arkansas Derby before running seventh to Super Saver in the Kentucky Derby. After finishing fifth in the Preakness, he was sidelined by chip in an ankle that needed to be removed.\r\nA son of dual classic winner Afleet Alex out of the Grade 1 winning mare Classy Mirage, Dublin was a $525,000 yearling purchase at the Keeneland September sale. He earned $438,949 with 2 wins from 11 starts for owners Robert Baker and William Mack.\r\n&ldquo;He&rsquo;s got a beautiful pedigree, and he&rsquo;s one of the best-looking horses I ever trained,&rdquo; Lukas said. &ldquo;He&rsquo;ll have a great chance to be a sire.