Two 3-year-olds being shipped to Churchill Downs for other races on Kentucky Derby (gr. I) week could join the field for the season's first classic.Trainer Tony Richey said Boyce Roberts' Arctic Boy may run in the Derby rather than a conditioned allowance race he is being pointed toward. Richey said a final decision on Derby plans for the son of Maria's Mon will be made following a Monday workout under jockey Calvin Borel."We're 50-50," Richey said. "A good work is going to help us a lot" in deciding which race in which to run.Richey said he began thinking about the Derby for the colt after he watched some of the leading contenders for the 1 1/4 mile race on the track. "I really started to think about it after watching the horses that are the favorites look like they backing up and maybe have peaked."A son of Maria's Mon, Arctic Boy has one win and three placings to his credit in seven starts. He was second in the Southwest and Rebel Stakes (gr. III) at Oaklawn Park before running last of 11 in the Arkansas Derby.Richey said the colt was unable to display his ability in the Arkansas Derby because the sloppy track jeopardized Arctic Boy's chances.Richey said Donnie Richardson, Churchill's vice president of racing, had been supportive of a possible Derby start by Arctic Boy. "He (Richardson) said you never know about what will happen in the Derby," Richey said. "We think he has a shot, but maybe not for all of it, we could be a good third or fourth. It is not like we have a maiden who has not run at a distance."If more than 20 horses are entered in the Derby, it would have the effect of ruling out a Derby bid by Tincin, a maiden who is scheduled to run.Richey said, however, he was not taking a shot at the connections of Tincin. "I have nothing against them" Richey said of Tincin's owners and trainer. "It they want to run in the Derby and put up their money, that is their privilege."Richardson said there is no concentrated effort on the part of the racing office to solicit Derby entries so Tincin would be excluded. He noted that there would have to be five or six new horses to the 14-horse list of probables for that to happen. Limited to 20 starters, the Derby field will be determined on the basis of earnings in graded stakes races if the race is oversubscribed.Meanwhile, Churchill officials said trainer Simon Bray could also decide to run Turf Paradise Derby winner Startac in the Derby rather than the Crown Royal American Turf (gr. IIIT), a 1 1/16-mile grass test on Friday's Kentucky Oaks card.