John Oxx accepts leading Epsom candidate Sea The Stars is not guaranteed to stay the mile-and-a-half trip of the Derby.The Cape Cross colt scorched to victory in the 2000 Guineas at Newmarket this month, but has yet to be tested over further than a mile.Oxx told the Times: "Everyone said he is a half-brother to Galileo, and therefore a Derby horse, but I knew he was speedy and his pedigree wasn't that of a stayer. I'd always had the Guineas in mind and he's no more than a 50-50 chance of staying the Derby distance. There are more negatives than positives in the breeding."Despite his concerns about Sea The Stars' stamina, Oxx is nonetheless expectant of a bold display.The County Kildare handler added: "He's a real tough horse, fine and big - you wouldn't find fault with him at all."Time will tell, but he looks to have all the temperament qualities you'd want for the Derby."We'd had to rush him a bit for the Guineas, so I'm happy it's a five-week interval before Epsom. That said, he's a very fresh sort and you wouldn't want to be giving him many days off."He cantered on the Wednesday after the Guineas and he looks well in himself. We never souped him up as a two-year-old, and he's still laid-back, but he does enough."