Leading jockey Joel Rosario has been cleared of charges that he failed to put forth his best effort in a turf race at Del Mar in September.\nIn a ruling issued Sunday, stewards Albert Christiansen, Kim Sawyer, and Randy Winick ruled unanimously that there was "insufficient evidence" to prove that Rosario failed to put forth his best effort on Cedros in the 11th race over a mile for maidens on Sept. 6.\nCedros, the 4-1 third choice, dueled for the lead for the first half-mile of the race, dropped back to fifth on the turn, and finished fourth, 3 1/2 lengths behind race winner Sterkel. \nThe California Horse Racing Board filed the complaint, which led to three days of testimony in November and earlier this month. The final day of testimony, and closing arguments, were conducted Friday. During closing arguments, Rosario's attorney, Roger Licht, said the racing board's case was "spurious" and described their investigation as "flimsy and inadequate."\nKenneth Jones, a deputy attorney general representing the racing board, focused part of his closing argument on Rosario's lack of a use of a whip in the stretch.\nCedros, trained by John Glenney, is winless in seven starts.\nRosario, 24, is the leading rider at the current Hollywood Park fall meeting and won riding titles earlier this year at the Hollywood Park spring-summer and Del Mar meetings.