Back in March, P.J. Fleck described defensive end Boye Mafe as "twitched up."

The Gophers coach couldn't hype up Mafe enough, glowing about the Golden Valley native's 40-inch vertical and impressive speed for a 6-4, 265-pound defensive lineman. By all accounts, Mafe was the heir apparent at rush end to Carter Coughlin, a current New York Giants linebacker who recently sacked Tom Brady.

"Sometimes you need a guy to graduate to really see the potential of somebody else," Fleck said eight months ago. "And I think that's a perfect [explanation of] what Boye's going through … because we see more leadership from him, we see more excitement, we see more productivity in two months than we had when he was No. 2."

Fast forward to the start of the season, and Mafe wasn't even the starter for the first two games. Thomas Rush, an offseason switch from linebacker to rush end, took the spot instead.

The Gophers were 0-2 to start the season, and Mafe started this past Saturday's 41-14 romp at Illinois. He leads the Big Ten with 3.5 sacks and is fourth on the team with 12 tackles.

But Fleck has wanted to see more.

"I don't think he's even started to scratch the surface of where he can go, and I've told him that," Fleck said Monday. " … Boye is going to be a really good player, and he's got to choose to be a really good player here. There is a lot of things that he can continue to get better at, especially in the run game. … He knows that."

Mafe has taken Fleck's words to heart, putting a lot of focus on growing individually and as a collective defense. The defense lost six starters from last season, many of them NFL-caliber talent. As a redshirt junior who played in every game in 2019's 11-2 season rotating in on pass-rush packages, Fleck seemed to look at Mafe as a potential leader on a young and inexperienced defense.

"The biggest thing I've been working on is finishing off my rushes, working on the top end and the rush," Mafe said. "Also talking with [defensive line coach Chad] Wilt and the rest of the D staff, they've been talking to me about different techniques to work on and different moves."

The defense allowed just 287 yards at Illinois, as opposed the 578 it had been averaging through the first two games. Still, it's a shadow of last season's defense and all of its Antoine Winfield Jr. interceptions and forced three-and-outs.

Mafe, though, still has shown himself as one of the more athletic defensive players, capable of making big plays — including a tipped pass that became a DeAngelo Carter interception, plus a forced fumble and a quarterback hurry.

"We are wanting those impact plays. We need those impact plays," Mafe said. "And I think the biggest thing is that we're working as a group. We're not trying to be out there as a bunch of individuals."

A standout at Hopkins High School, Mafe emphasized that most interceptions start with a quarterback pressure, most sacks are a product of defensive line effort, and that he's just trying to continue to contribute to that.

His coach will take notice if he does.