On 7 February 2006, having not played for Birmingham since 28 December 2002 nor any team since 10 January 2004, Sadler made his return in a 2–1 home win over Reading in an FA Cup fourth round replay, coming on for Mathew Birley after 59 minutes. This was his only appearance until 1 April when he was in the first team to play Chelsea at home, a goalless draw. He stayed in the starting line-up for the remaining games, as the season ended with relegation. At the end of the 2005–06 season, Sadler was awarded the Radio WM Breakthrough Award at the club's annual dinner. Not only that, Sadler signed a two–year contract with the club.