BALTIMORE—Medina Spirit is set to run in the Preakness Stakes on Saturday to go for the second leg of the Triple Crown, as long as the Kentucky Derby winner passes a series of additional drug tests. Maryland racing officials reached an agreement with trainer Bob Baffert on Tuesday to allow Medina Spirit and his other horses to enter races this weekend at Pimlico Race Course subject to extra testing and monitoring. If Medina Spirit, who failed a postrace drug test after winning the Kentucky Derby, comes back clean in test results expected Friday, he is likely to be the favorite to win the Preakness. “We reached an agreement with Mr. Baffert and his lawyers that allows for additional testing, additional monitoring—essentially a watchlist to ensure the integrity of the sport leading up to the race,” Maryland Jockey Club lawyer Alan Rifkin said. “We’re very pleased to have that and we …