per DRF article below, he passed daily drug tests...but will have back surgery.
Injury knocks Valenzuela from meet
By STEVE ANDERSEN
DEL MAR, Calif. - \"Jockey Patrick Valenzuela will not ride at Del Mar this summer because of a back injury, according to his agent, Tom Knust.
Knust said that Valenzuela was advised on Friday that the back injury will require surgery and that he could be out from four to eight weeks. If that time frame proves correct, Valenzuela could return for the start of the Oak Tree at Santa Anita meeting on Sept. 27.
\"He\'ll probably have to have surgery,\" Knust said. \"He won\'t be here at this meeting. They\'re going to run more tests on Monday or Tuesday.\"
Valenzuela, 43, has not ridden since July 16, the final day of the Hollywood Park spring-summer meeting. He finished second in the standings to Victor Espinoza during that meeting. Earlier this year, Valenzuela won the riding title at the Santa Anita winter-spring meeting.
Valenzuela was excused from his mounts from Wednesday through Friday at Del Mar and was not named to ride over the weekend.
Knust said that during the time he is off, he is also likely to undergo treatment for a recurring knee problem.
Valenzuela, who has a history of substance abuse problems, underwent daily drug tests from Wednesday through Friday at his home by California Horse Racing Board investigators and passed each test, Knust said.\"