Kanaan's team, Andretti Green Racing, and Hornish's team, Team Penske, were fined $25,000 each for unsportsmanlike conduct on pit road as the cars returned after the checkered flag. The teams are also on probation until Dec. 31.

The altercation at the Watkins Glen Grand Prix broke out when the drivers exited their cars. Hornish's father pushed Kanaan, then was knocked to the ground by members of Kanaan's crew.

"We believe that emotions play a role in our sport but it is unfortunate that others took it as an opportunity to become involved," said Brian Barnhart, president, racing and operations division for the IRL.

Sam Hornish Sr. has been suspended from pit lane for one race and was also placed on probation until Dec. 31, the IRL said. Anthony Fedele has had his league-issued hard card, which was granted through Andretti Green Racing, and credential request opportunities suspended indefinitely.

"We are disappointed in the actions of the drivers, the team members and the non-team members involved in the incident," Barnhart said. "Entering the field of play even after the checkered flag and actively becoming engaged in anything outside of celebration is inappropriate and inexcusable."