There remains a chance Michael Tabor and Mrs. John Magnier's Johannesburg could make his 2002 debut on the grass at The Curragh in Ireland April 7 rather than at Lingfield the previous day, trainer Aidan O'Brien said April 2. A decision must be made by the evening of April 4, he said.The first preference is the group III Gladness Stakes at seven furlongs on the grass at The Curragh, O'Brien said. Much depends on the weather, which is "so changeable. It's very hard to call. The last few days it has dried up, so it looks like he could go to The Curragh," he said.If Johannesburg goes to The Curragh, Castle Gandolfo, another of O'Brien's 3-year-olds, will race on the all-weather track at Lingfield in the Foster's Invitational. If Johannesburg races at Lingfield, Castle Gandolfo will compete in the Gladness.Meanwhile, Johannesburg, the 2001 champion 2-year-old colt or gelding, is in good form and training nicely, O'Brien said."I couldn't be happier at this stage," O'Brien said. "Hopefully, he'll have a nice race (this weekend) and finish with plenty in hand."O'Brien made his comments during a media teleconference. When asked whether he believes the Hennessy colt could be ready for the May 4 Kentucky Derby off only one prep race in Europe, O'Brien said: "The reality of this fellow is he was probably a freak as a 2-year-old. No challenge seemed too big for him. We're hoping he'll be a freak at 3."O'Brien indicated the question of whether Johannesburg can get the 1 1/4-mile distance will be answered on Derby Day. He noted the colt made the transition from six furlongs to 1 1/16 miles with no problem when he won the Bessemer Trust Breeders' Cup Juvenile last fall at Belmont Park.