United finally won promotion to the Premier League in the 2005–06 season, finishing runners up in the Championship, during which Kozluk played 27 league games. A further 20 first team appearances followed in the top flight the following season but the club failed to consolidate their top-flight status and were relegated in a final day show-down with Wigan Athletic. With the club looking to rebuild and cut costs Kozluk was released by United at the end of the season. At the time of his departure he was United's longest serving player, having made 236 league and cup appearances for the club.