On 22 August 2012, Wolves accepted an offer from Sunderland of £12 million. Fletcher signed a four-year contract with Sunderland. He made his first appearance for Sunderland in a 2–0 win against Football League Two club Morecambe in the Football League Cup. Fletcher then scored his first two goals in his Premier League debut for Sunderland, a 2–2 draw at Swansea City. He also scored once in each of his next three league matches, against Liverpool, West Ham United and Wigan Athletic. He won the Premier League Player of the Month award for September. After a run of games without a win, an injury sustained playing for Scotland in March 2013 ruled Fletcher out for the rest of the 2012–13 season.