Arizona secondary of primary concern for Chicago Bears

Unlike last week, the Chicago Bears' top three wide receivers all were healthy this week and enjoyed two straight days of full practice, giving quarterback Jay Cutler a complete arsenal of weapons and the offense more big-play potential.

Then Pro Bowler Alshon Jeffery's hamstring tightened up at the end of Thursday's practice, leaving the pass-catching crew less than 100 percent for Sunday's game against the Cardinals and their super-talented secondary.

Even at full strength, teams are leery of an Arizona secondary that features two of the league's most spectacular players, cornerback Patrick Peterson and safety Tyrann Mathieu.

Mathieu, an all-rookie performer in 2013, led the defense with 8 tackles last week and set a personal best with 3 pass breakups.

"Mathieu, he's everywhere," said Bears wide receiver Eddie Royal, who was held to just 1 catch for 8 yards last week but will play a bigger role if Jeffery is out. "If you put on the tape, he stands out to you, just flying around making plays in the run game and also getting his hands on the ball in the pass game."

Rarely does an offensive line worry about a 5-foot-9, 186-pound defensive back like Mathieu, but he's a rare player.

"He's active, he's fast and he's aggressive," Bears guard Matt Slauson said. "So any time one of us is responsible for him, we have to make sure we're on our toes, ready to move and then, as soon as he gets close, we have to really lay wood on him."

Peterson has been voted to the Pro Bowl in each of his four seasons - the last three as a cornerback. He made it as a returner in his rookie season, when he brought 4 punts back for touchdowns. Peterson has 15 interceptions (tied for second in the NFL) since he was the fifth overall draft pick in 2011, and is one of the freakiest athletes in a league that has many of them.

"He's physical, great ball skills, able to just mirror guys - it's almost like the receivers are telling him what route they're running before the play," said Bears offensive coordinator Adam Gase. "The guy's a phenomenal player, and he's a tough matchup for whoever ends up on him."

If Jeffery can't play or is limited, Royal and Marquess Wilson will see much more of Peterson, and they won't see many cornerbacks as talented - until the following week when they face Richard Sherman and the Seattle Seahawks.

But first things first.

"We know that they've got great players in the secondary, but we've got great players on our offense, too," Royal said. "We know it's going to be a great challenge, but we've got a great bunch of guys who are up for that challenge."

The Cardinals are well known for mixing it up on defense, which will leave their defensive backs in a lot of 1-on-1 situations.

"They're not afraid to play man," Cutler said. "They're not afraid to come and get you and bring more (pass rushers) than you are capable of blocking."

That should create opportunities for big plays from the Bears' wide receivers.

"I hope so," Cutler said. "They've had a good week (of practice). All of those guys have competed hard out there. We'll see what we have on Sunday."

Peterson and Mathieu both possess elite ball skills with the ability to make plays on the ball like a wide receiver, which Peterson has played from time to time for Arizona.

"They're great in coverage, as we all know," Royal said. "But it's their ability to get their hands on the ball and then make plays after that. They both create challenges, and (Jerraud) Powers is a great corner, too. He's been around for a while, he's experienced, and he knows how to play the game."

How well the Bears' wide receivers play against that group will go a long way toward determining Sunday's outcome, and without Jeffery there's a lot of slack to pull. The wide receivers caught 8 passes for 145 yards vs. Green Bay in Week 1, and Jeffery led the way with 5 catches for 78 yards.

• Follow Bob's Bears and NFL reports on Twitter@BobLeGere.