Clint Frazier’s future in doubt again now that Gardner’s back

After missing almost a week because of an inflamed right knee that underwent an MRI exam, Brett Gardner returned to the top of the Yankees’ lineup Friday. Gardner, who hadn’t played since last Saturday versus the Rays at Yankee Stadium, missed five games while Aaron Hicks (four) and Clint Frazier (one) hit leadoff. “I think…