The NFL is suspending Denver Broncos safety Kareem Jackson four games after his hit on Minnesota Vikings quarterback Joshua Dobbs Sunday night.

The league announced the suspension Monday afternoon.

The suspension is the second of the season for Jackson for repeated illegal hits to the head of opponents. Per the report, the suspension is for repeated violations of the player safety rules.

Jackson lowered his helmet and hit Dobbs in his facemask on the first possession of Denver's 21-20 win. The hit dislodged the ball and resulted in a forced turnover for the Broncos, who converted the fumble into a field goal.

Officials did not flag Jackson for the illegal hit.

The NFL announced the suspension alongside a letter to Jackson from vice president of football operations Jon Runyan.

"With 13:38 remaining in the first quarter, you were involved in a play that the league considers a serious violation of the playing rules," Runyan wrote. "The video of the play shows that you lowered your head and made forcible contact to Vikings quarterback Josh Dobbs. You had an unobstructed path to your opponent and the illegal contact could have been avoided.

"Illegal acts that are flagrant and jeopardize the safety of players will not be tolerated. The league will continue to​ stress enforcement of the rules that prohibit using your helmet to make forcible contact with your ​opponent. On the play in question, you lowered your head and delivered a forceful blow to the shoulder and head/neck area of an opponent when you had time and space to avoid such contact. You could have made contact with your opponent within the rules, yet you chose not to."