PORT ST. LUCIE — The Mets are portraying it as just a precaution, but it has to be considered worrisome nonetheless: Johan Santana is being scratched from his scheduled start tomorrow morning against Italy’s WBC representative because of tenderness in his left elbow. Jerry Manuel told reporters of the decision late this morning. … 1:05 P.M. UPDATE: Santana just told us the problem is minor enough that he would be able to pitch if this were the regular season. He said he remains on track to make his spring-training debut here next Tuesday against the Cardinals. “I’m just worried about [the regular-season opener on] April 6,” he said.