Calgary Stampeder Jon Cornish has been fined for mooning Saskatchewan Roughriders fans after a 30-25 loss at Mosaic Stadium in Regina on Sunday.

The CFL issued a short statement on Monday afternoon, saying it has fined the Stampeders' starting running back an undisclosed amount "for his inappropriate conduct towards CFL fans."

Earlier in the day, Cornish said the move was a big mistake on his part.

"I definitely just took it one step too far, or maybe a few steps too far," Cornish said.

"You know, it reflects poorly on the organization, so first of all I want apologize to coach Huf, all the coaches, my teammates, all the Stampeder fans, the Stampeder organization and the Rider fans — 'cause they don't deserve that, I mean no fans deserve that." 

Cornish also tweeted on Monday that his "conduct last night was unbecoming of a professional athlete."

Stamps general manager John Hufnagel said he is very disappointed in Cornish's conduct.