The discipline came as a result of Castroneves' meltdown following last month's race in Edmonton, Alberta, in which he was stripped of the victory for blocking his Team Penske teammate Will Power and failing to take the drive-through pit-lane penalty.
The Brazilian confronted two officials on pit lane after the conclusion of the race, making physical contact with one of them after exiting his car.
"I fully support the decisions of chief steward Brian Barnhart and Race Control," IZOD Series chief executive Randy Bernard said. "The drivers have been aware of the blocking rule for quite some time."
Bernard said suspending Castroneves was considered as an option, but added, "We felt suspension would hurt the fans more than anyone else."