ENGLEWOOD, Colo. --When he was suspended four games to open the 2015 season, Derek Wolfe not only vowed that the mistake would not be repeated, but declared that he would return hungrier -- and better -- than before.

He did.

For the last 12 games, he ran roughshod through opposing offensive lines, using his power and resolve to push opposing guards and tackles backward. After three seasons of ups and downs -- some of which were exacerbated by injuries that sunk his second NFL season and detoured his progress -- Wolfe became the interior force the Broncos long believed he could be.

"We've seen improve over the four years that he's been here -- especially this year -- and he's just gotten better and better," said Executive Vice President/General Manager John Elway.

That's why the Broncos wanted Wolfe back on the four-year contract extension to which they agreed Friday.

"Last night, I called my agents, and the deal was already on the table, and I said, 'Look, let's just take this deal,'" Wolfe said. "I don't want to leave. I love the city, I love the team, I love the organization, the coaches, my teammates and everything.

"I couldn't be happier. I'm in a place that I love to be, so why would I leave?"

And, indeed, the Broncos feel the same way: Why would they want to let him leave?

Improvement in 2014 has led to dominance in 2015 -- so dominant, in fact, only three 3-4 defensive ends have higher overall ratings from profootballfocus.com since Week 5 than Wolfe, who grades out as the league's second-best run-defending 3-4 end in that span.

"He's only scratched the surface, and we really think that Derek has a tremendous amount of football ahead of him," Elway said, "and that's why we're so excited that it's going to be in Denver."

Wolfe earned AFC Defensive Player of the Week honors in Week 8 despite not posting a sack, a testament to the impact of pressure and being a terror against the run. He single-handedly forced a three-and-out with two run stuffs that gave the ball back to Denver's offense; by the time Green Bay saw the football again, the Broncos led by 17.

Wolfe didn't notch a sack that night, but it didn't matter. However, as a player who always wants to deliver more, it rankled him.

"Anytime I don't get a sack, I don't think I had a good game," Wolfe said after that performance. "Sacks aren't rolling around as much as they used to anymore with [OLB] DeMarcus [Ware] and [OLB] Von [Miller] and [DE] Malik [Jackson] and Shaq [OLB Shaquil Barrett] now. There are so many guys that can rush the passer that it's almost like, even if you do have a good rush, it's not good enough because they're just a little bit faster."

The lack of sacks would soon change for Wolfe. They have come -- at least a half-sack in six consecutive games to end the season, beginning with a bull rush that led to a sack of New England's Tom Brady in the Nov. 29 win.

"That's what he's worked on," Defensive Coordinator Wade Phillips said at the time. "He's a strong player, so [Defensive Line Coach] Bill [Kollar] has gotten him to work hard on more of a power rush -- we call it a bull rush, but it's more of a power rush -- and be able to come off and make plays in the passing game."

This breakout season may just be the beginning for Wolfe. The conversion to the 3-4 alignment brought him to a position to which he appeared best suited when he came into the 2012 NFL Draft after a stellar career at the University of Cincinnati that culminated in a Senior Bowl invitation.

The Broncos were in their second season in the 4-3 alignment when they picked him in the second round of that draft, and he did well in spurts, although a neck injury and subsequent complications wrecked his 2013 and derailed his progress. In 2014, he got back on track, and formed a formidable inside-rush partnership with Malik Jackson.

But with Phillips, arrival, the 2015 change in alignment and the arrival of the fiery Kollar, everything came together.

"[Kollar] has made me better in so many different aspects as far as hustle, using my hands more, getting my hips turned," Wolfe said in November. "I'm not going to give away all my secrets, but he's taught me a lot of different things. He's good at taking a guy, figuring out what he's good at and forcing him to do those things."

Wolfe has always set up his teammates for sacks; Miller estimates he has "30 to 35 sacks" playing alongside Wolfe, whose interior rush has freed Miller and Ware for one-on-one matchups that they can exploit.

But with Wolfe racking up sacks of his own in recent weeks as the defense overcame injuries to finish as the league's top unit in total defense, passing defense and average yardage per play allowed, he's taken his game to the next level.

"I said it before the season -- it was going to be a different Derek Wolfe," Miller said in November. "I don't think he's finished yet."

With this extension, the Broncos are counting on this being just the beginning of prime years and elite performance from the energetic, nasty 3-technique end that they've nurtured into one of the league's best at his position.

"We're always looking for players that want to be Denver Broncos," Elway said, "and Derek wanted to be a Denver Bronco, and we wanted him to be a Denver Bronco."