LOUISVILLE, Ky. - The Stonestreet Stables of Jess Jackson announced Wednesday that it had reached an agreement to purchase Rachel Alexandra, the sensational winner of the Kentucky Oaks last Friday at Churchill Downs, from owners Dolph Morrison and Mike Lauffer.\nTerms of the deal were not disclosed. A source close to the negotiations said that Rachel Alexandra would be transferred to the barn of trainer Steve Asmussen as soon as Thursday.\nThe sale raises the possibility that Rachel Alexandra could be supplemented for a $100,000 fee to the next jewel of the Triple Crown, the May 16 Preakness at Pimlico. The filly was not nominated to the Triple Crown, and Morrison, her breeder and co-owner, was adamant in the wake of her Oaks victory that she would not be supplemented to the Preakness or the Belmont Stakes, the final race of the Triple Crown series on June 6.\nNegotiations picked up speed Wednesday morning after Rachel Alexandra "vetted out perfectly," according to the source, who cited a confidentiality agreement that precluded speaking on the record.\nIn a statement, Jackson said that at the conclusion of her racing career, Rachel Alexandra would be bred to Curlin, the 2007-08 Horse of the Year. Stonestreet is the majority owner of Curlin, who was retired to stud last fall.\n"She is fast, strong, and durable - the traits we should all be breeding into all future generations of race horses," Jackson said in his statement.\n"We are tremendously excited by the prospect of one day seeing the offspring of Curlin and Rachel Alexandra," he said. "But for now, the story of this filly is still being written."\nOwned by the L and M Partners of Morrison and Lauffer and trained by Hal Wiggins, Rachel Alexandra won the 135th Oaks by 20 1/4 lengths, the widest winning margin in the race since 1910, the earliest date for which Churchill has such records. She earned a Beyer Speed Figure of 108 in the Oaks. The 3-year-old daughter of Medaglia d'Oro has won her last five starts.\nAsmussen, who trained Curlin for Jackson, said Wednesday afternoon that he had not been told that the filly would be joining his stable.\nMeanwhile, Rachel Alexandra made her first appearance on the racetrack since the Oaks when out for a 1 1/4-mile jog early Wednesday under regular exercise rider Rudy Gallegos. Until the possibility of a sale arose, she had been scheduled to train at Churchill until leaving a few days before her next scheduled start, the Grade 1 Acorn on the Belmont Stakes undercard.