ENGLEWOOD, Colo. -- Denver Broncos safety Kareem Jackson has been suspended without pay for four games for repeated violations of player safety rules, the result of his first tackle since he returned from another suspension.
Jackson lowered his helmet and hit Minnesota Vikings quarterback Joshua Dobbs less than two minutes into Sunday's 21-20 Broncos win.
A 14-year veteran in his fifth season with the Broncos, Jackson was notified of his suspension Monday morning by NFL vice president of football operations Jon Runyan. Runyan said in the letter, "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.''
Dobbs was a running back on the play, as Vikings tight end T.J. Hockenson took the snap from center and pitched the ball to Dobbs, who ended up fumbling.
One of the NFL's health and safety spotters on site directed Dobbs to undergo a concussion check following the play. Dobbs was cleared and reentered the game for Minnesota's next offensive series.
Jackson, who was not penalized on the play, plans to appeal the suspension, sources told ESPN on Monday night. He had a four-game suspension reduced to two games on appeal earlier this season.
Jackson would forfeit $559,889 in salary if the current four-game suspension is upheld. He has been fined four times this season for unnecessary roughness for a total of $89,670 and has been ejected from two games.
He was suspended for four games after his hit on Green Bay Packers tight end Luke Musgrave in Week 7. After his appeal reduced the suspension to two games, he missed the Broncos' Week 8 win over the Kansas City Chiefs as well as the team's Week 10 win over the Buffalo Bills and forfeited $279,000 of his base salary.
He returned against the Vikings, playing all 74 of the Broncos' defensive snaps.
Following the game, Vikings coach Kevin O'Connell was asked if he felt Jackson should have been penalized on the play.
"On the field, it felt like that," O'Connell said. "I'll have to go back and look at it. It tends to happen pretty fast out there, but in the moment, coming from the second level the way he did, it seemed like a pretty direct helmet-to-helmet type hit. But I'm sure [officials] saw it differently on the play. They're officiating a fast play right there.''
Broncos coach Sean Payton said Monday morning, several hours before the NFL announced the suspension, that he had spoken to Jackson and added, "There's nothing you can do except wait, and we'll see where it goes.''
Dobbs said he "felt fine'' after the hit and deferred to O'Connell on whether Jackson should have been penalized.
"I haven't had a chance to watch it," Dobbs said after Sunday's game. "That's something I'll check out. I've got to take care of the football. Third-and-1, I'm trying to make a play, get the first down, keep us on the field, move the sticks. I'll let the coaches and everyone else figure that stuff out with officiating. But at the end of the day, I've got to take care of the football in that situation, especially to start the game.''
The Broncos are riding a four-game win streak and will face two other teams hoping to stay in the playoff race -- the Cleveland Browns and the Houston Texans -- over the next two weeks. The Broncos then play at the Los Angeles Chargers on Dec. 10 at SoFi Stadium and at Detroit Lions on either Dec. 16 or Dec. 17.
Jackson said last week he had talked to league officials to seek "clarity'' on tackling, including the plays for which he had been penalized. After his earlier suspension, Jackson's teammates were quick to defend him, especially safety Justin Simmons, who took exception to the league's letter to Jackson last month notifying him of the suspension as well as the narrative that Jackson is a dirty player based on the fines and ejections.
"Even referring to the letter that was sent to Kareem that, in so many words, called him a dirty player, that bothers me as a teammate,'' Simmons said at the time. "I would not be half the player I am if it wasn't for Kareem, if it wasn't for the knowledge he has bestowed upon me, both on and off the field.
"The whole 'dirty player' analogy we're kind of trying to stick to his name and his reputation is, excuse my language, absolute bulls---."
Simmons defended Jackson again on social media Monday night after the suspension was announced.
ESPN's Kevin Seifert contributed to this report.