Hornish returned to the Sprint Cup Series for one race in Penske's No. 12: the STP 400 at Kansas Speedway. Starting in 10th place, he led for seven laps and finished 19th (one lap behind). Midway through the season, Hornish replaced A. J. Allmendinger in Penske's No. 22 car after Allmendinger was suspended by NASCAR for failing a drug test. Allmendinger qualified in eighth place, but due to the driver change Hornish had to move to the rear of the field. He finished 33rd, after a mid-race crash required ten laps of repair time. Hornish drove the car in the remaining races, with a season-best fifth place at Watkins Glen. Aside from that race, his best finishes were a trio of eleventh places at Atlanta, Richmond and Chicagoland. Hornish's best start of the season was fourth at Dover, where he finished 25th (seven laps behind).