McAfee applauds Russell Wilson, Broncos after win over Vikings (1:50)Pat McAfee believes Russell Wilson has steered the narrative back in his direction with a big win over the Vikings. (1:50)
Hearing officer Derrick Brooks, jointly appointed by the NFL and NFL Players Association, declined to reduce the suspension after Jackson appealed the initial decision.
Jackson will miss games against the Cleveland Browns, Houston Texans, Los Angeles Chargers and Detroit Lions. He will be eligible to return in Week 16, a Christmas Eve home game against the New England Patriots.
Earlier this season, Jackson had a four-game suspension reduced to two games by Brooks on appeal. The Broncos' game Sunday night against the Vikings was Jackson's first in his return from that suspension.
Less than two minutes into Sunday's game, Jackson lowered his helmet and hit Dobbs, who was a running back on the play after Vikings tight end T.J. Hockenson took the snap from center and pitched the ball to Dobbs.
Dobbs, who ended up fumbling, subsequently underwent a concussion check but was cleared to reenter the game.
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.''
With the four-game suspension upheld, Jackson will forfeit $559,889 in salary. He has already been fined four times this season for unnecessary roughness for a total of $89,670 and has been ejected from two games.
Jackson said last week that 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.
Information from ESPN's Jeff Legwold was included in this report.