GREEN BAY—Clay Matthews and B.J. Raji both used the same word, and it has given these two Packers veterans a different feel about the 2014 defense.

On Monday, both Matthews and Raji applied the word "tenacity" to what they've seen from this year's defense in the preseason. The first unit has only been on the field for a handful of game series so far, but that limited action has provided legitimate building blocks. The rest is up to them.

"I always have a positive outlook on our defense, but this year, especially when you look around at the guys, they exude a certain type of energy and a certain prowess about them," Matthews said, referring to newcomers Julius Peppers and Ha Ha Clinton-Dix as well as several veterans.

"Everyone up and down the board, it just seems like a team that's been together for a while, who really has something to prove, and I think you're going to see that. I'm excited about that. I'm excited every year, but it's about proving it."

Thus far, the Packers have proven to be rather stout against the run. On Saturday, the No. 1 defense held the Rams' No. 1 running back, Zac Stacy, to a net of just six yards on six carries. Four times, Stacy was tackled in the backfield for losses.

The Rams did score a touchdown on their second drive, with the help of a third-down pass interference penalty that moved the ball into the red zone. But overall Matthews liked the "continuity" he's sensing from the unit, which is largely a function of few injuries. Raji also threw out the words "mentality" and "pursuit."

"Thus far we've shown that we have those things, but we have to keep improving because our competition is going to get much stiffer," Raji said.

Clinton-Dix kept the competition at safety in the spotlight Monday with two interceptions in practice, which was moved indoors to the Don Hutson Center due to rain. The rookie first-round pick caught an overthrow from fourth-string QB Chase Rettig and ended the No. 1 offense's two-minute drill when a twice-deflected dump-off pass found his waiting arms.

"It's starting to slow down a lot," he said of the speed of the game. "I'm starting to be a lot more consistent, just flying around the ball and having fun. It felt great to actually touch the ball again after a while."

Combined with key moments in each of the two preseason games – a pass breakup deep down the middle in Tennessee and then a sack on a blitz in St. Louis – Clinton-Dix's progress has been evident, though not flawless.

He may have been a tad overzealous early in the St. Louis game, when he took a bad angle on receiver Brian Quick, allowing Sam Bradford's completion to rupture into a 41-yard catch and run. He didn't have a chance to break up the play, but he did have the opportunity to limit the gain if he hadn't overrun Quick.

"He's doing a good job of learning from his mistakes and moving on," fellow safety Micah Hyde said. "He's a football player. He has really good instincts, and he's out there making plays right now."

How the competition ultimately shakes out between Hyde and Clinton-Dix for the starting job opposite veteran Morgan Burnett is anyone's guess at this point. The only given seems to be that Hyde and Clinton-Dix are both going to play in Dom Capers' various packages, and play plenty.

"He'll draw up some stuff to get guys on the field and get guys in position to make plays," Hyde said of Capers. "We know that. We're going to keep competing, trying to get on the field."

The rest of the preseason will also be about players fighting to make the team, and undrafted rookie Jayrone Elliott is trying to state his case at a crowded outside linebacker position. In a four-play span in the fourth quarter against the Rams, Elliott recorded three sacks, forcing a fumble on one of them.

"That was just crazy," Elliott said. "A lot of people started calling me by my name instead of my jersey number. It was a great moment out there."

The little-known Toledo product said he's rarely gotten more than a few reps in a row during camp, but perhaps now he's earned some more.

"I heard he's starting this weekend in front of me," Matthews joked. "It's good to see. I'll be rooting for him. I'll be rooting for all of (the young guys) moving forward."