He scored a goal, as well as, setting up two goals in his first appearance, in a Scottish League Cup tie against East Fife on 7 August. A week after he sustained an injury during a match which ruled him out for weeks, On 2 September 2012, Shiels scored his first league goal, as well as setting up a goal, in a 5–1 win over Elgin City. After scoring two goals in three games, Shiels scored against the Scottish Premier League side Motherwell, in a Scottish League Cup tie. Then, in the Scottish Cup, Shiels scored twice and earns a hat-trick assist, as Rangers thrashed Alloa Athletic 7–0 on 3 November 2012. During the 2012–13 season he missed five months of the season due to a medial knee ligament injury.