Sadler joined League Two club Shrewsbury Town on 7 July 2010 on loan for six months. According to manager Graham Turner, the player seemed reluctant initially to play in the fourth tier of English football but was won over by the club's ambition. Sadler made his Shrewsbury Town debut in the opening game of the season, in a 3 – 1 win over Bradford City. In the next game, Sadler played a role for the club when he provided assist for Matt Harrold to score the only goal in the game in a 1–0 win over Macclesfield Town. Since then, Sadler made an impressive display at Shrewsbury Town, having established himself in the first team and expressed interests of extending his loan spell at the club for the remainder of the season. On 6 January 2011 saw Sadler's loan spell at Shrewsbury Town extended until the end of the season. During the match against Port Vale on 8 March 2011, Sadler controversially fouled Tom Pope in a penalty box, leading to a penalty kick converted successfully, which resulted a 2–2 draw. Despite this, Sadler went on to be an ever-present player in the League Two season to play every minute of every game for his club. Sadler played in two matches in the play–offs against Torquay United, but lost 2–0 in the first leg and drew 0–0 in the second leg.