SPARTANBURG — The Panthers have known for some time they probably needed another pass-rusher.

But Sunday's addition of veteran Justin Houston wasn't just about filling one position.

Adding a player of his caliber can change the entire defense, primarily by keeping the entire defense from having to change.

There are things the Panthers knew walking into a new system this year. That Brian Burns could get to quarterbacks is a given since he has 38.0 sacks in four seasons, is coming off two straight Pro Bowls, and is still just 25. (For context, Hall of Honor defensive end Julius Peppers had 40.5 sacks in his first four seasons.)

But the unknowns beyond Burns were going to force the Panthers to adapt.

Without a second known commodity on the other side, they were likely going to have to adjust on the fly and move people around to create the kind of pressure they need to make defensive coordinator Ejiro Evero's scheme work.

That could take on a lot of forms, from using a committee that included Marquis Haynes Sr. (currently sidelined with a back issue) and a number of young players to turning the rest of the depth chart into a chess board.

The Panthers know that Frankie Luvu can get to a quarterback based on last year. Luvu set single-season career highs for tackles (111), tackles for loss (19), and sacks (7.0) last season. Luvu is capable of a lot of things but is the kind of energy player that can make a quick impact on any game from a lot of different places.

That's why head coach Frank Reich described him as "the steal of the century." But they also didn't want to rob the base defense just to deploy him as a rusher.

In this 3-4, he's starting inside next to Shaq Thompson, which keeps him from pinning his ears back and attacking the quarterback as often as he has in the past.

Last week's addition of linebacker Deion Jones, along with an impressive early camp from Kamu Grugier-Hill, would have given the Panthers other proven players at that position, which would ostensibly free Luvu up to rush the passer more.

Same with Jeremy Chinn, who struggles at times to describe his job description because it's kind of hard to put him in a box.

But by playing nickel in this system, he'll be back in the box. He can use his defensive back-speed to help cover and his playmaking instincts to be closer to the line of scrimmage.

You've already seen evidence in training camp of Evero moving him around, blitzing him, and sending him from different alignments and angles.

"One of the first things we said when we got here is that this guy is a weapon; he's a different type of player with that size, that speed, his skill set, the way he can affect the game in so many different ways," Evero said of Chinn. "And it's our job as a staff to make sure that we're utilizing them as such. And so far, so good. He's been he's exactly where we want him to be. You know, I don't want to give too much away in terms of how we want to utilize him. But this guy is a weapon, and we've got to make sure that we put him in position to affect the game.

"Now I think we got a good idea about where he is, you know, when you go through the whole offseason, and you go through this first part of training camp. And Jeremy is so good about communicating with the coaches and talking to the coaches, asking questions, getting up, and doing extra time. So I feel like we've developed a really good rapport with him. And I think we got a good feeling of where he's at."

Then there are the young pass-rushers, from Yetur Gross-Matos to Amaré Barno to third-round pick DJ Johnson, and even players like Kobe Jones and undrafted rookie Eku Leota (who has put together a solid camp). They're a little bit like lottery tickets at this point. You don't know which one, if any, will turn out to be the kind of pros they need. But maybe they hit.

But Evero made it clear last week that he definitely needed another one to hit quarterbacks.

"You know, we need somebody to step up," Evero said. "That's a fact. And we got to just continue to push those guys toward it."

Asked about potential reinforcements from outside the roster, prior to the addition of Houston, there was also an underlying message from the new coordinator.

"Yeah, I mean, we feel good about where our guys are right now," Evero said. "We love our roster, especially at that position. And, you know, there's going to be great competition for that spot. And it's not just going to be one guy.

"You just can't have two rushers in this league; you've got to have multiple guys that could get the job done. And we feel good about where the guys are going, though."

Senior defensive assistant Dom Capers knows that you need two. When he started with the Panthers in 1995, he had Lamar Lathon on one side, and he was very good. But adding Kevin Greene the following year took the defense to a new level, and they went to the NFC Championship Game. The second one makes a huge difference.

That's not to say Houston's a future Hall of Famer like Greene. But they do feel better about where they're at now.

Houston is 34 years old, but he has continued to produce at a high level throughout his career.

He had 19.0 sacks in two seasons under Reich in Indianapolis (2019-20) and had 9.5 sacks last year for the Ravens (including half a sack against the Panthers last November).

He's never matched the 22.0 sacks he had for the Chiefs in 2014, but the simple fact he's been a consistent producer since then (111.5 in 12 seasons, 27th on the league's all-time list in that category) has its own value.

Unlike other pass-rushers, he's also of some utility on running downs, and that's a part of this equation they didn't ignore when putting together their offer.

Is it reasonable to expect him to be a double-digit sack guy? Maybe, maybe not. We'll see. But the man has had at least 8.0 sacks in eight of his 12 NFL seasons, so it is reasonable to expect him to impact a game.

But perhaps as much as anything else, he gives the Panthers a chance to keep from having to impact their entire defensive scheme, moving guys all over the place, and drawing stuff in the dirt to manufacture pressure.

That could be worth as much as anything Houston himself provides.