GREEN BAY -- Pittsburgh's base defense is a classic 3-4, and even though like all teams the Steelers play more sub-packages than base these days, it's the front seven that sets the tone on a very tough unit.

"They're salty. They're built for it," Packers Head Coach Mike McCarthy said of Pittsburgh's 3-4 foundation, which Green Bay will face on Sunday night at Heinz Field. "It plays to the strength of their front seven. It's clearly reflected in their statistics, how well they play the run and transfer it to the pass rush and pressure schemes."

The Steelers rank fourth in the league in yards allowed and second in points allowed. They've racked up 34 sacks in 10 games, with four players totaling four or more, led by defensive lineman Cameron Heyward with seven.

They've also intercepted 12 passes, including four in their last game against Tennessee. Linebacker Ryan Shazier has three picks, and he's one of nine players with at least one interception on the season.

"There's a lot of production throughout their defense," McCarthy said.

On the injury front for the Packers, McCarthy said defensive lineman Kenny Clark (ankle), linebacker Clay Matthews (groin) and running back Ty Montgomery (ribs) would all start with the rehab group on Wednesday.

Rookie cornerback Kevin King, who missed last week's game with a shoulder injury, was slated to work his way back into practice.

"It's definitely impacted his play and his preparation," McCarthy said of King's shoulder. "It's something he's been dealing with all year. He's fighting through it, and he wants to give it a go today. It's a constant that he's dealt with really since training camp."

Packers.com will have more following practice and locker room interviews.