NASCAR has fined at least two of its star drivers this season for making critical comments about the racing series, The Associated Press has learned. People familiar with the penalties told the AP the comments were considered disparaging to the sport. The people spoke on condition of anonymity because NASCAR was not publicly identifying the topflight drivers it fined. They say one driver was penalized as much as $50,000. NASCAR spokesman Ramsey Poston on Monday night confirmed some action had been taken, but would not discuss details. "It is the sanctioning body's obligation on behalf of the industry and our fans to protect the sport's brand," Poston said. "Any action taken by NASCAR has nothing to do with the drivers expressing an opinion -- it's focused on actions or comments that materially damage the sport. http://sports.espn.go.com/rpm/nascar/news/story?id=5411570