IndyCar has fined Panther Racing owner John Barnes and placed him on probation until the end of the year for posting a critical comment on Twitter.

IndyCar said Saturday that Barnes was fined $25,000 and put on probation until Dec. 31 for using "improper or disparaging language in reference to IndyCar."

Barnes can appeal the penalties. He admitted in a statement he "should have chosen a more private forum to voice my opinions."

The Panther owner tweeted on Thursday: "Today is the day to resolve TURBOGATE! I hope (at)indcar gets their act together. It has been embarrassing."

He was referring to a hearing to decide whether Honda would be allowed to make changes to its turbochargers, which eventually happened.

Panther Racing uses engines from Chevrolet, which had appealed a decision by IndyCar allowing the changes that eventually added power to the Hondas. A three-person panel upheld the series' decision at a hearing in Indianapolis on Thursday.

"Nobody cares about open-wheel racing and the Indianapolis 500 more than I do, and therefore I'm very passionate about all the decisions that are made — right or wrong — that affect our sport," Barnes said.

"While my passion for this sport will never waver, I should have chosen a more private forum to voice my opinions."

The team, preparing for Sunday's Sao Paulo 300, said it has not yet decided whether it will appeal.

There hadn't been a fine meted in IndyCar because of Twitter comments since three-time Indianapolis 500 champion Helio Castroneves last year posted comments criticizing then chief steward Brian Barnhart. Castroneves was fined $30,000 for calling Barnhart a "circus clown."