DETROIT — The Detroit Tigers have dropped one veteran right-handed reliever and added another. Carlos Hernandez was designated for assignment after pitching in back-to-back games this week in Pittsburgh. His spot will go to Geoff Hartlieb, whose contract was selected from Triple-A Toledo before the Tigers’ series opener against the Toronto Blue Jays on Thursday. Hartlieb, 31, signed a minor-league deal with the Tigers 10 days ago and made two appearances for the Mud Hens. He had been designated for assignment earlier this month by the New York Yankees and then elected free agency after clearing waivers . Hartlieb has pitched in parts of six big-league seasons for five different teams, though