Oswalt threw a wild pitch to Jason Kubel with Eric Chavez on third base. Chavez scored on the error, and Oswalt injured his leg attempting to cover home. The veteran starter could barely walk after covering home, per Pleskoff, and exited the game after the play.
Oswalt may have pulled his left calf or hamstring, Troy Renck of the Denver Post is speculating, but the team has yet to announce an official injury.
Sunday's start against Arizona was Oswalt's fourth of the season since signing a minor league contract with Colorado on May 2. The starter had struggled in his three previous starts, going 0-3 with a 7.88 ERA. Oswalt has flashed signs of effectiveness, striking out 21 batters while only issuing two walks in 16 innings.