Canelo Alvarez pulled out of his much anticipated fight with Gennady Golovkin yesterday in the wake of his positive drug tests earlier this year. The fight, scheduled for May 5, was expected to be a highlight of the boxing year. Their first bout last September ended in a draw. Golovkin is 37-0-1, and Alvarez is 49-1-2. The Ring Magazine currently ranks Golovkin as the best pound-for-pound fighter in the world, with Alvarez at No. 4. Alvarez had tested positive for clenbuterol on Feb. 17 and 21. He claimed that the result came because he had eaten tainted meat in Mexico, where clenbuterol is sometimes given to animals. Clenbuterol is used by some athletes to drop body fat and weight.