Mercilus was fined for a play where his helmet hit the chin of Flacco. Mercilus was given a penalty for roughing the passer on the play.
Baltimore won the game 30-9 to give Houston its first loss of the season.
Mercilus spoke after practice on Wednesday, and says he plans to appeal the fine.
The second-year player has 13 tackles and a sack this season.
More Sports Headlines
Silvertips beat Portland 4-3 to improve to 3-0 in preseason Seahawks trade running back Michael to Cowboys for draft pick AquaSox host Dust Devils in Game 1 of playoff series on Monday night Mariners beat A's 3-2 for season-best fifth win in a row Edwards holds off Hamlin to win NASCAR's Southern 500 After losing to Portland State, Cougars try to rebound against Rutgers Serena beats Keys, meets sister Venus in U.S. Open quarterfinals Source: Packers, WR Jones agree on 1-year contract
Our new comment system is not supported in IE 7. Please upgrade your browser here.