Pittsburgh Steelers cornerback William Gay has been fined $15,750 (£9,600) by the NFL for an illegal hit on Cleveland Browns quarterback Jason Campbell.
The incident occurred during the Steelers' 27-11 victory last Sunday, although Gay was not penalised at the time.
The fumble his tackle caused led to a touchdown scoring drive for his team, but the league have since deemed it not legal, stating that it should have been reviewed.
Gay's side are 5-7 in the AFC North, as they hunt for a playoff spot.