GREEN BAY – Defensive lineman Mike Pennel is projected to be a player of distinct importance in Sunday's season opener at Soldier Field.

"Our goal is to improve our run defense. That's what we've been working on and, hopefully, it'll come true," Packers Defensive Line Coach Mike Trgovac said in previewing Sunday's game between the Packers and the Bears.

Pennel, a second-year player who made an impression as an undrafted free agent in 2014 and then built on that impression in this year's training camp, will be filling in for two suspended defensive linemen, Letroy Guion and Datone Jones. Guion is arguably the Packers' best run-stuffer.

"He's a big man, so he has the ability that if he doesn't do something right, he can cover it up with his size," Trgovac said.

Stopping Bears running back Matt Forte is at the top of the Packers' to-do list for this game. Pennel will be joined in the effort by veteran nose tackle B.J. Raji and defensive end Mike Daniels, the Packers' best defensive lineman. Raji, of course, missed all of last season due to injury.

"I just want him to do his job," Trgovac said of Raji. "If everybody did their job, that turns into a special defense. B.J. has been excellent. He's been durable in training camp. He never asked for a rest."

Durability will be at the test on a sunny day this Sunday, especially considering the Packers will be depleted up front.

"We're facing a really good back," Trgovac said.

"If you can't be physical against the run, you're fighting an uphill battle," Defensive Coordinator Dom Capers said. "We've placed a priority on it. We know we're going to be challenged early, especially with a couple of linemen not being in there."

The Packers offense is being challenged by a familiar foe, Bears Defensive Coordinator Vic Fangio.

"We played against him in San Francisco for a number of years, so there's some familiarity on both sides," Packers Associate Head Coach and play-caller Tom Clements said.

Will Fangio rush or cover?

"We have an anticipation for how it might go. He picks his spots. I don't want to give away our thoughts," Clements said.

Special Teams Coordinator Ron Zook said rookie wide receiver Ty Montgomery will "probably" return kickoffs.

"I feel like (Montgomery) is coming into his stride. You can feel it coming on. I'm excited about him," Zook said.

Punter Tim Masthay had been in a slump until the final preseason game, his best of the four. Zook says Masthay is ready for the regular season.

"Tim's hitting the ball well. When Tim relaxes and hits it, he's pretty good," Zook said.

The games begin to count on Sunday. It's no longer the preseason.

"That's a good quote. It's not the preseason," Clements said.

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