ARCADIA, Calif. – Exercise rider Adrian Valenzuela sustained a spinal-cord injury in a spill at Santa Anita on Saturday and did not have feeling in his legs on Sunday morning, according to his father, trainer Martin Valenzuela. Adrian Valenzuela, 21, was scheduled to undergo surgery on Monday at Huntington Memorial hospital in Pasadena, his father said. Martin Valenzuela said Adrian suffered a “fractured back.” Doctors have told Martin Valenzuela that his son could be paralyzed from the waist down. “They have to get some inflammation out of his back,” he said. “Hopefully, the feeling will come back to his legs, but they said it’s a small chance.” The injury occurred when Adrian Valenzuela worked a horse for trainer Bobby Wayne Grayson. One of the bandages on the horse’s front legs became unraveled, causing the horse to stumble and fall, Martin Valenzuela said. Martin Valenzuela works closely with Grayson. “The bandage came off,” Martin Valenzuela said. “I don’t know if it ripped.” Adrian Valenzuela has worked primarily as an exercise rider in recent years. He rode briefly at the Los Alamitos night meeting in 2016, winning one race from eight mounts. “He got a little heavy,” Martin Valenzuela said.