Gino Castignoli, who lives in The Bronx, confessed to the New York Post last week that he buried a Red Sox slugger David Ortiz jersey at the site last summer while working at the stadium. Two construction works went to a manager saying they believed the knew where Castignoli must have buried the shirt. Workers brought out jackhammers and dug furiously for five hours, creating a 2-foot- by-3-foot, gravel-filled pit in their search for the tainted threads. They spotted the jersey at 3:25 p.m. and called Yankee brass. The shirt was about two feet deep in cement. "They absolutely pinpointed that if it was in the ground, that's where it was," team spokeswoman Alice McGillion said, as she let The Post inspect the now partly buried shirt.