After the season concluded, a budget decrease led Kelley Racing to reduce its roster from three to two cars, leaving Renna without a race seat; he remained an employee of the team. Renna continued to work as Unser's spotter and drove go-karts to maintain his fitness. The difficulty in finding sponsorship to compete in races restricted Renna primarily to being a test driver, but he made a single race appearance in the 2003 IndyCar Series, the Indianapolis 500. Starting from eighth place, Renna finished in seventh. In Indianapolis, Chip Ganassi Racing (CGR) managing director Mike Hull told team owner Chip Ganassi that Renna was a driver to take notice of. In October 2003, Ganassi offered Renna a driving role in his team for the 2004 IndyCar Series in place of Tomas Scheckter— who moved to Panther Racing—and to partner 2003 IndyCar Series champion Scott Dixon. Renna accepted the role; Tom Kelley allowed him to leave on October 1 and join CGR, because he could not guarantee Renna would drive for Kelley Racing in 2004.