Any air of invincibility surrounding the New England Patriots appears to be gone for this season. The Denver Broncos probably never thought it was there to begin with.

The Broncos look to continue their long-standing dominance over the Patriots when they travel to Foxborough for a Monday night matchup of AFC contenders trying to avoid consecutive losses.

Since losing reigning league MVP Tom Brady to a season-ending knee injury in the first quarter of their opener, the Patriots (3-2) have shown little resemblance to the team that posted the first 16-0 regular season in NFL history in 2007. Led by career backup Matt Cassel, the offense has struggled to move the ball, scoring 20 points or more only once in five games.

The defense has also had problems, giving up 89 points while losing two of the last three games. Big plays are proving to be an Achilles' heel for New England, which is allowing 5.92 yards per play -- 27th in the NFL. San Diego's Philip Rivers victimized the secondary for three completions of 48 yards or more last Sunday night, helping the Chargers hand the Patriots a 30-10 defeat.

"Anytime the ball gets thrown over your head in the secondary, that's not good," Patriots coach Bill Belichick said. "It is every defensive back's job to keep the ball in front of them."

Cassel completed 22 of 38 passes for 203 yards, but got intercepted for the third consecutive week and was sacked four times. He has shown a lack of mobility in the pocket, as his 19 sacks are the most among AFC quarterbacks.

Cassel also isn't getting much help from a running game which has yet to produce a 100-yard individual effort. Starter Laurence Maroney sat out for the third time this season due to a shoulder injury last week, and his status for Monday is uncertain.

New England is trying to avoid losing three times or more in four games for the first time since a four-game losing streak from Sept. 29-Oct. 27, 2002. The final game of that skid was a 24-16 home defeat to the Broncos.

Denver won at Gillette Stadium on Sept. 24, 2006, overcoming a 320-yard effort from Brady to beat the Patriots 17-7. Including playoff matchups, the Broncos have won 16 of the last 19 meetings between these original AFL franchises.

Big plays have also plagued Denver's defense, which is yielding an AFC-worst 6.24 yards per play. The Broncos (4-2) have allowed 400 or more total yards three times this season, including 416 in last week's 24-17 home loss to Jacksonville.

Denver, which benefited from a key blown call in a 39-38 win over San Diego in Week 2, this time found itself on the other end of controversial officiating. Defensive backs Dre' Bly and Marlon McCree got flagged on questionable interference and illegal contact calls to extend Jaguars drives -- leading Bly to question the motives of the referees.

"I guess they've been evaluating us and say we won games we shouldn't have won. So, I guess they're going to get a call against us," Bly said.

The NFL fined Bly $20,000 on Friday for those remarks.

Working against the Broncos more than any officiating crew is an offense that has cooled after a torrid start. Denver, which scored 34 points or more in each game of its 3-0 start, has failed to reach 20 points while dropping two of its last three.

Jay Cutler continues to be effective, with at least one touchdown pass in each game and a 94.8 passer rating. Despite another solid effort last week, though, Cutler failed to reach 200 yards for the first time in 2008, completing 21 of 37 passes for 192 yards, two TDs and one interception.

The first of the two scores was an 11-yard strike to Brandon Stokley, who found the end zone for the second consecutive week. Stokley finished with three receptions for 29 yards, but also suffered his 10th career concussion. In order to play Monday night, he'll need to pass a series of mental acuity tests.

"I don't want to be a liability out there," Stokley said. "And I don't want to be a vegetable when I'm 50."

Much like the Patriots, Denver is dealing with uncertainty at running back. Selvin Young sat out the Jacksonville game due to a groin injury, and rookie Ryan Torain has to yet to play in the regular season while he recovers from a broken bone in his left elbow.

Eleven-year veteran Michael Pittman filled in admirably for Young last week, gaining 109 yards on 20 carries for his first 100-yard effort since 2005, when he was with Tampa Bay.