GREEN BAY – The Packers-Bears rivalry is an old one. This will be a new version.

"This is a unique opener," Head Coach Mike McCarthy said prior to Green Bay's Wednesday practice as the team gets ready to host Chicago on Sunday night at Lambeau Field. "A division rival, new offensive scheme, new head coach, a premier player acquired on (Saturday)."

The new head coach is Matt Nagy, who will be making his head coaching debut. The premier player is pass rusher Khalil Mack, who held out all of training camp and the preseason until Oakland traded him.

McCarthy said history would dictate that in a season opener, roughly 35 percent of the plays and packages an opponent will bring in are "unscouted," and he doesn't expect this opener to deviate from that with so many changes in Chicago.

"That's what we've been preparing for, and I think it'll probably hold true Sunday night," he said.

The Packers have plenty of changes as well, of course, particularly on the defensive side of the ball with new coordinator Mike Pettine and a number of new players, including veterans Tramon Williams and Muhammad Wilkerson along with rookies Jaire Alexander and Josh Jackson.

The team has been building to this point, and while it's a long season with plenty of evolution ahead on the defensive side, getting started right is a priority.

"We're ready to go," McCarthy said. "I'm past the changes, and I'm excited to take the next step with all the new individuals."

There are fewer new guys on an offense that now includes tight end Jimmy Graham. Up front, right guard Justin McCray is the only new starter – though he started several games at multiple positions last year.

Injuries across the offensive front prevented the starting five from working together a whole lot through the preseason, but McCarthy is putting his faith in the veteran experience of the group to make the transition to the regular season a smooth one.

Right tackle Bryan Bulaga, coming off the second ACL injury of his career, is in his 10th season, while left tackle David Bakhtiari is in his sixth, center Corey Linsley is in his fifth, and left guard Lane Taylor is entering his third year as a full-time starter.

"I think you just have to believe in the men," he said. "Obviously we haven't practiced a whole lot together, the offensive line that's projected to start in this game. Hopefully the good Lord touched us and we got our injury phase out of the way.