Letourneau-Leblond, who was assessed a minor penalty for boarding on the play, is considered a repeat offender under the terms of the league's collective bargaining agreement, as he was suspended for one game last season. He will miss Calgary's remaining four preseason games and the Flames' Oct. 8 home opener against the Pittsburgh Penguins.
Letourneau-Leblond violated the league's expanded boarding rule that was created during the offseason. Players must now make sure that an opponent isn't defenseless when a hit is delivered.
"Letourneau-Leblond took a direct route toward Clackson, hit him squarely from behind into the boards and drove through the check high and hard," Shanahan said in a statement. "Clackson's back was turned toward Letourneau-Leblond well before the contact, requiring that Letourneau-Leblond avoid or minimize the check. He did neither."
The proceeds from the fine will go to the Players' Emergency Assistance Fund.
Information from The Associated Press was used in this report.