CHARLOTTE – Coming off a 15-1 season and considering the Panthers' depth of talent in the interior of their defensive line, most viewed the first-round selection of defensive tackle Vernon Butler as a "luxury pick" in 2016.

But the Panthers picked Butler because they thought he represented a bargain at No. 30 given his wealth of ability, and both Butler and the Panthers hope to cash in on that potential on the heels of an uneven but valuable rookie campaign.

"I had my ups and downs. Gotta get better," Butler said recently. "It was an OK year, but this year will be better – I'll tell you right now."

As much as is possible during offseason workouts, Butler backed up his words. The 6-4, 325-pounder commanded the attention of his defensive coaches – and the attention of the offensive coaches squaring off against him.

"I'm very impressed with what he's doing," new defensive coordinator Steve Wilks midway through offseason training. "He is prideful right now. I mean, lights out."

The light flickered on and off for Butler last season, often the case for first-year pros and doubly so for those forced to fight health concerns along with the other rookie rigors.

Butler saw some action in the first three games of the season – recording his first sack in his first game – but a high ankle sprain suffered in Week 3 sidelined him for five games. He played in nine of the final 10 game and still showed flashes, but the injury interruption proved hard to overcome.

"It played a part because I wasn't 100 percent. I was more 75, 80 percent most games," Butler said. "But I've just got to move on from that, have a better year this year."

Butler provided a glimpse of how disruptive he can be by knifing/powering through to block a pair of field goals over a six-week span down the stretch, joining Julius Peppers as the lone Panthers with two blocks in a single season. Getting to a kick isn't the same but obviously shares some of the characteristics needed to get to the quarterback, and Butler said fundamentals work with defensive line coach Eric Washington this offseason has "made me a whole lot better."

It seems like the offseason as a whole is having that impact.

"I feel way more comfortable than last offseason, feel more comfortable in the system," Butler said. "I learned a lot last year from Coach Washington, and now I'm eager to get even better.

"It feels different. Last year everything was moving so fast, going from college to pro. But now I feel like I'm settled in pretty good and ready to go."

He's ready, and so is the entire defensive line group. Peppers, a five-time Pro Bowler with the Panthers from 2002-09 who added four more Pro Bowls elsewhere, has returned to an intact line that helped Carolina rank second in sacks last season.

"This is a special group here," Butler said. "We've got a great coach and a great group of guys. We have some great pass rushers and some great leaders. The sky is the limit."