The regular season hasn’t started yet, but Iowa’s defensive coordinator Phil Parker thinks his defensive-end cadre could be deadly.

Freshman A.J. Epenesa, sophomore Parker Hesse, and juniors Anthony Nelson and Matt Nelson make up Iowa’s top-four defensive-end rotation.

“I think it’s the best we’ve been up front as a whole since I’ve been coordinator here,” he said.

2017 marks Parker’s 19th season with the Hawkeyes — he’s seen his fair share of defensive-line talent during his tenure.

This season’s corps possesses a unique blend of experience and raw talent.

“I think we’re moving along,” head coach Kirk Ferentz said at Iowa’s media day. “[The defensive end group is] really kind of an open book right now. We have a bunch of guys competing.”

Last season, the two Nelsons solidified themselves as one of the Big Ten’s up-and-coming defensive-line duos.

The Nelson duo, the Nelson and Nelson law firm — whatever you want to call them — combined for 75 tackles last season, including 11 sacks and 14 tackles for a loss.

Add in a pair of forced fumbles and fumble recoveries for good measure.

RELATED: Football PCP: Iowa’s preseason predictions

Matt Nelson started alongside Hesse in 2016.

Hesse, who racked up 36 tackles, 7.5 tackles for a loss, and 3.5 sacks last season, started all but one game, which he missed because of an injury.

“We have guys who are capable of playing, capable of having an impact sitting everywhere in the room,” Hesse said.

The defensive-end trifecta disrupted things up front last season, but the final addition to the quartet came from Epenesa.

The freshman came to Iowa City as the Hawkeyes’ most coveted recruit to date.

Parker noted that even though the regular season hasn’t kicked off, Epenesa has “shown some promise” in his practicing.

“I think he has real good potential,” Parker said.

RELATED: Transfers look for immediate impact

A five-star prospect from Edwardsville, Illinois, 247 Sports ranked the freshman as the best defensive end in the country and the 27th-best prospect overall in his class.

Epenesa’s commitment and arrival on campus left Iowa fans salivating; his skill set combined with an already-promising defensive-end rotation shaped up for an enticing line this season.

“We take a lot of pride as a D-line, as a unit,” Hesse said. “So anybody we can get who’s going to help the whole improve, we’re excited about.”

When asked if Epenesa would play in the opener, given that Iowa already possesses talent up front, Parker responded without hesitation: “No question.”

Good defense stems from pressure; if opposing quarterbacks face a rush every time they drop back, they make rash decisions, which makes the linebackers’ and secondary’s job that much easier.

Attempting to maximize his personnel group, Parker has worked Matt Nelson on the inside, allowing three of his defensive ends to take snaps at the same time.

“He already knows [the] outside,” Parker said. “He’s been a great team member, saying, ‘Hey, let me take some reps.’ It’s a little harder to take a young guy and say, ‘Hey, you can play two positions.’ I think Matt can play two positions.”

Epenesa might not be locked into playing outside as well.

“It’s a lot easier to move Matt inside a bit and leave A.J. where he’s at, and let’s see if we can gradually move him in at some point,” Parker said.

No matter who plays where on the line, the Hawkeye defensive ends thrive in a versatile system – Parker explained that in years past, he’d sub out a lineman for an additional linebacker to help with the pass rush, but he figures the frequency of that to diminish this season.