As Tony Romo and the Dallas Cowboys prepare for the Denver Broncos this Sunday, the quarterback knows he's in for a challenge against one of the league's most potent offenses, but it was the Broncos secondary that Romo turned his attention to on Tuesday, accusing them of having a reputation for holding and not being penalized.

"They grab, they hold, they've almost put a lot of pressure on the refs - whether or not they're going to call the game close or not," Romo said per Yahoo! Sports. "If they get called once or twice, that's a good thing. But they're all over guys as far as using the little tricks, I guess you could say, that good linebackers and good secondaries use when they're playing man coverage."

Romo said that the Broncos' (4-0) secondary doesn't get punished enough, according to USA Today Sports, although it has been penalized 10 times this season, five stemming from defensive pass interference, four from holding and one for illegal contact.

Romo has led the Cowboys to a 2-2 record this season, while going 110-for-152 (72.4%) for 1,015 yards with eight touchdowns and one interception. The Cowboys defeated the New York Giants on opening night, dropped a close game to the Chiefs in Week 2, slaughtered the Rams in Week 3 and are coming off of a loss to Chargers by a 30-21 score in Week 4.

While Dallas has managed some success, Sunday afternoon's game will be a tall task despite the fact that the team is playing at home. It hasn't mattered where Peyton Manning has played the first four weeks of the season as he is off to one of the best starts of all-time. Manning has completed 117 of his 156 attempted passes for a league-leading 1,470 yards and a record 16 touchdowns through four games and no interceptions.

The Broncos mowed down the defending Super Bowl champion Baltimore Ravens in Week 1 before Manning led the team to a win in Manning Bowl III against his brother Eli and the New York Giants in Week 2. The team then beat the Raiders in Week 3 and destroyed the Eagles in Week 4 by a 52-20 margin.

Whether or not Romo's comments will affect the way the referees call the game remains to be seen, but perhaps it's not the defense the Cowboys should be worried about as Denver's Peyton Manning-led offense has been downright scary through the first four weeks of the season.