Wesolowski played for Australian side Northern Spirit before signing for Leicester City in 2002. After showing a lot of potential in the reserves, Wesolowski played for Leicester in a pre-season friendly against Celtic in 2005, but suffered a broken leg due to a challenge from Bobo Baldé. He underwent surgery on the leg but the injury sidelined him until the start of 2006. Wesolowski returned and impressed for the Leicester first team, making his debut at home to Cardiff City in January 2006. However, after only five appearances, he broke his same leg against Brighton in February.