by Dan LaulettaNorberto Arroyo Jr. won the first race of the Belmont Park meet May 7, but his day was cut short by a frightening spill at the start of the fourth race.Shoo Brush stumbled and dumped Arroyo at the start of the race, and as the rider's momentum brought his head up off the ground, he was struck by one of Shoo Brush's rear legs. Nearly the entire team of assistant starters rushed to Arroyo's aid as he writhed in pain.Arroyo eventually boarded the ambulance under his own power. Later, he seemed to be dazed, and had large bruises on his face, neck, and chest.Shoo Brush ran off but was not injured.Arroyo is in the midst of a wild year. He injured his shoulder during the first week of the year, then spent more than a month in jail for a pool-hall fight last summer. He also won the biggest race of his career when he steered New York Hero to victory in the Lane's End Stakes March 22 at Turfway Park. He no longer rides for New York Hero's owner, Ernie Paragallo.