At the start of the 2010–11 season, Treacy started things well when he scored the winning goal in a 2–1 win over Bradford City. In the local-rivalry against Burnley on 11 September 2010, Treacy scored and provided an assist for Jon Parkin, in a 4–3 loss. He scored his second League Cup goal of the season on 22 September 2010, in a 2–1 loss against Wigan Athletic, eliminating Preston North End from the League Cup. Treacy then scored two goals in two consecutive matches between 28 September 2010 and 2 October 2010 against Leeds United and Reading. However in a match against Derby County on 16 October 2010, he was sent–off for a second bookable offence after giving away a penalty at the last minutes, as the club lost 3–0. After serving a one match suspension, Treacy returned to the starting line–up against Crystal Palace on 23 October 2010, and "fired home from all of 35 yards for his sixth goal of the season", in a 4–3 win. His goal against Crystal Palace later earned him Goal of The Season Award at Preston North End’s Award Ceremony. Since joining the club, he continued to regain his first team place throughout the 2010–11 season. Treacy then provided seven assists in nine matches between 15 February 2011 and 19 March 2011. During in which, he scored his first goal in five months against Scunthorpe United, in a 3–0 win on 15 March 2011. A month later on 16 April 2011, Treacy scored a brace, in a 3–1 win against his old club, Sheffield United. However, Preston North End were relegated to League One, following a dismal season with only 42 points. Even though Preston North End were relegated to League One, Treacy finished the 2010–11 season with and making forty-one appearance and scoring nine times in all competitions.