Dean Shiels last home match of the 2008–09 season, when he scored the first goal in a 2–0 victory over Crystal Palace. Shiels scored six goals in 42 games during the 2009–10 season. However, during the 2010–11 season Shiels lost his place in the Doncaster starting line-up. He was loaned to Kilmarnock in July 2011 and his contract was mutually terminated in January 2012. Shiels signed a six-month loan deal with Kilmarnock, managed by his father Kenny Shiels, in July 2011. Shiels made his first appearance for Kilmarnock on 30 July 2011, in a goalless draw against Motherwell at Rugby Park, coming
Kenny Shiels from dropping down at the end of the season. Shiels responded by making a number of big name signings, including Tommy Wright, Paul Beesley and Liberian international Leon Browne, but none of them proved a success and the club finished in fifth place. The club improved significantly in the 2002–03 season, although ultimately they managed only second place in the First Division, as well as the Ulster Cup and the Country Antrim Shield. The league position was enough to ensure promotion, although the club had led the table until near the end when Dungannon Swifts took over at the top.