Jeff Allen is entering his 18th year as Alabama’s head athletic trainer. But for the last 17 years, he has worked under the same head coach – Nick Saban. When Saban retired in January, Allen was retained by new head coach Kalen DeBoer and will continue to serve in his official title as the associate athletic director of sports medicine for Crimson Tide athletics. Allen has now spent seven months getting to know DeBoer, and he described the transition from Saban to Alabama’s new coach as he joined Hey Coach on Wednesday evening. “I’ve worked for the same head coach for a long time, but one thin…