In 1989, Sullivan suffered a broken arm in a crash during practice for the Indy 500, and would miss two races. He rebounded to win the Pocono 500 in August - his second win in that event - and one other race to place a respectable 7th in points. Sullivan's last season with Penske Racing was 1990. He won two races in 1990, including the season finale at Laguna Seca. He won the pole and led wire-to-wire in his final start for Roger Penske.