"Clay Matthews is not an inside linebacker," McCarthy said on Monday, one day after Matthews had a career-high 11 tackles and one sack while dividing his time between inside and outside linebacker in the Packers' 55-14 rout of the Chicago Bears. "He's a football player."
And against the Bears, he was a good one.
"I thought he had an outstanding football game. He was able to impact the game in a lot of different areas," defensive coordinator Dom Capers said Monday.
"He's still in our third downs and was rushing from outside. We were able to rush him from both inside and outside, and he flowed to the ball and had a lot of production. It worked the way we wanted it to work."
Looking to bolster their NFL-worst run defense and get their best 11 players on the field at the same time, McCarthy and Capers lined Matthews up at inside linebacker for 38 of the 53 snaps he played.
It was a wrinkle they'd come up with during the offseason and training camp but installed after the team's bye, intent on using it against the rival Bears.
Earlier in the season, the Packers had Matthews moving around their defense pre-snap as well.
But many of the times he lined up in the middle of the defense, it was when they were using a four-man front with only three linebackers.
On Sunday, Matthews was used as an inside linebacker in the Packers' nickel defense — two down linemen, four linebackers, five defensive backs — and then shifted to his normal outside position to rush the passer off the edge in the dime group.
"The focus (during the offseason) was to play more players on defense, move Clay around and create challenges for the offense," said McCarthy, whose Packers (6-3) are one game behind the Detroit Lions (7-2) in the NFC North. The Packers host Philadelphia at Lambeau Field on Sunday.
"We'll see where he plays this week."
Capers also wouldn't say if Matthews' move is permanent.
"Every week your plan is a little different depending on what you feel you've got to do to win the game," Capers said.
And while players had the day off for "Victory Monday," Matthews chose his words carefully when asked how he liked his new position.
"I don't know. I mean, I was in great position to make a lot of plays and I think that's ultimately the reason why we needed to make a few changes around here," Matthews said.
"I've always taken pride in whatever they've asked me to do, so you put me in position where there's some free space and some opportunities to make some plays, I took advantage of it. So, I think this is what we wanted out of this change and we'll see what that means going forward."
Rushing from the outside, Matthews actually had two sacks, although the second was nullified when he was flagged for a personal foul for striking Bears quarterback Jay Cutler in the head. Matthews' best play came late in the second quarter, when the Bears ran an end-around to wide receiver Chris Williams.
Matthews began the play lined up inside, but shifted outside just before the snap, the Bears failed to locate him and he dropped Williams for an 8-yard loss just as he got the ball.
"He almost took the handoff and hit the reverse guy in the backfield," Capers said. "Those are the types of things that you like to see. I think they create more problems for preparation when they aren't sure exactly where Clay is going to be."
The only drawback for the Packers is that the Eagles won't be surprised by seeing Matthews moving around, as the Bears were.
"That's the benefit of an unscouted look," McCarthy said. "Now, Week 2 will be different and it obviously goes away. But it has its benefits the first time out of the box."
The Packers' defense, which was up-and-down during the first half of the season, hopes it has more surprises and more good performances ahead.
The Bears only managed 55 yards rushing on 24 attempts. In the teams' Sept. 28 meeting, Chicago ran for 235 yards — and turned the ball over three times on a pair of Cutler interceptions and a fumble on a sack.
"Our goal is this second half of the season to play with more consistency in what we did. I thought we had some very good defensive outings the first half of the season, but there was too much inconsistency," Capers said.
"We know we have a really good, productive offensive team coming in here (in the Eagles) this week, that it's going to take a really good effort against them.
"As you look around this league, with every team, there aren't many who haven't had a few of those tough bumps in the road. Our goal is to hopefully keep that arrow pointing up this second half of the season."