DEL MAR, Calif. &ndash; Jockey Patrick Valenzuela, whose career has been plagued by substance abuse problems that have resulted in multiple suspensions, was approved to resume riding in California for the first time in nearly three years by the California Horse Racing Board on Thursday.\r\nValenzuela&rsquo;s request for a license was approved by the racing board following a closed-door executive session on Thursday afternoon.\r\nValenzuela will be subject to a stipulated agreement that he submits to several forms of testing, including through hair follicles. In a statement, the racing board described the agreement as &ldquo;unprecedented due to its continual nature and strict conditions.&rdquo;\r\nRacing board officials have been in contact with Louisiana state racing officials, including the California board&rsquo;s former executive director, Roy Wood, who told California officials that Valenzuela has passed drug and alcohol tests while licensed in that state.\r\nAccording to the agreement in California, Valenzuela will be prohibited from possessing, injecting or consuming &ldquo;all psychotropic (mood-altering) drugs, including alcohol, and be subject to random biological fluid and drug screening testing, including hair-follicle testing, for the detection of alcohol, narcotics, hypnotics, dangerous drugs or other controlled substances.&rdquo; Failure to comply with those tests would result in a suspension, the statement said.\r\nIn addition, if Valenzuela violates federal, state or local laws, he must notify the board in writing with 72 hours, and he must attend three meetings a week for treatment of alcoholism through the Winners Foundation, which provides counseling for people in horse racing with substance abuse problems.\r\nValenzuela took a hair-follicle test in mid-July, and tested negative, the racing board&rsquo;s chairman, Keith Brackpool, said in an interview at Del Mar racetrack on Thursday. Brackpool said Valenzuela&rsquo;s testing &ldquo;is continual while he rides.&rdquo;\r\nValenzuela has ridden in Louisiana and New Mexico in recent years, but has not ridden in California since December 2007 following a drunken driving arrest. His conditional license was revoked in September 2008 when the racing aboard adopted the decision of an administrative law judge. At the time, the racing board ruled that Valenzuela &ldquo;is permanently ineligible to reapply for, or to hold, a license issued by the California Horse Racing Board.&rdquo;\r\nSince then, the racing board has experienced turnover of several members, including the addition of Brackpool and vice-chairman David Israel.\r\nValenzuela, 47, won the 1989 Kentucky Derby on Sunday Silence. He has won 4,141 races in his career. It was not immediately known when Valenzuela would resume riding in Southern California. He recently hired Tom Knust to be his agent, and the two were on the backstretch at Del Mar earlier this week.