ARCADIA, Calif. – An untimely setback has knocked California’s top sprinter out of the Breeders’ Cup Sprint. Cistron, whose victory in the Grade 1 Bing Crosby Stakes at Del Mar earned a fees-paid berth in the BC Sprint, is out until early next year, trainer John Sadler confirmed on Thursday. “He tweaked his back, and he needs about 30 days off,” Sadler said. :: BREEDERS’ CUP 2019: See DRF’s top contenders Although the setback occurred at an inopportune point in the 2019 racing season, at least Cistron will return next year. “We did the diagnostics, and it’s nothing bad,” Sadler said. “He’ll definitely be back, probably early 2020.” Cistron was a capable turf sprinter until Sadler returned him to dirt this spring at Santa Anita. He responded with three top efforts to emerge as the top sprinter on the circuit, He won the Grade 2 Kona Gold Stakes by more than five lengths, finished second after setting a fast pace in the Grade 2 Triple Bend at seven furlongs, followed by a gate-to-wire victory in the six-furlong Bing Crosby at Del Mar. A 5-year-old sired by The Factor, Cistron has won five races and $700,719 from 27 starts, all for Hronis Racing. Bing Crosby runner-up Desert Law also is sidelined with an unspecified injury. Although the top local sprinters are missing, the Grade 1 Santa Anita Sprint Championship on Saturday attracted an interesting field. East Coast-based 3-year-old Shancelot and the comeback 3-year-old Omaha Beach top the six-horse field. Sadler trainees Flagstaff and Horse Greedy also were entered.