After an October 2011 match between Kilmarnock and Hearts which resulted 1–0 win for Kilmarnock, Grainger was criticised by Kilmarnock striker Dean Shiels, who branded him a coward following an incident in which Grainger's studs landed on Shiels' back while he was face-down. Grainger was suspended for two matches. His absence from the Hearts team was then prolonged by a groin injury, for which he needed an operation. In the Scottish Cup Final in the Edinburgh derby, Grainger scored a penalty on 48 minutes after Pa Kujabi was sent off which was his first goal.