It’s not easy replacing your leading rusher.

That’s what Northwestern was tasked with before its season opener when Cam Porter went down with a season-ending leg injury. Porter was expected to lead the running game once again after a breakout freshman season. Suddenly, it was about “next man up.”

That’s where Evan Hull came into the picture.

Hull assumed RB1 duties after Porter’s injury and has become one of the bright spots for coach Pat Fitzgerald’s group. He’s Northwestern’s leading rusher, averaging 87 yards per game.

The run game has been a big part of Northwestern’s offense, which saw a quarterback change in Week 4. Hunter Johnson was benched and South Carolina transfer Ryan Hilinski was in against Ohio. But that didn’t matter. It was Hull who stole the day.

Hull ran 22 times for a career-high 216 yards and 2 TDs — going 90 yards on 1 of them — to lead the Wildcats to a 35-6 win. It was the kind of game Northwestern needed after a rough loss to Duke in Week 3.

Let’s put it in perspective. Last year, Hull ran for 209 total yards over 9 games as a 4th-string RB. He ran for more than that in Week 4 of this season alone. Still not impressed? He already has more rushing yards in 4 games than Porter did over 9 games last year.

Yeah. You’ll want to learn his name, especially with B1G play starting next week.

Hull has rushed for 100+ yards twice this year — against Indiana State and Ohio. He might’ve hit 100 in the season opener if he’d have gotten any carries in the 1st quarter;  he finished with 87 yards over the final 3 quarters. But we saw him struggle in the loss to Duke, when he didn’t even crack 50 yards. The Ohio game was a good bounce-back, though, and he could be finding a groove.

That groove could help the Northwestern offense really get going.

Through 4 games this season, the Wildcats are averaging 211.5 rush yards per game — 4th-best in the B1G — and 174.25 passing yards per game. With Hull sitting comfortably in the RB1 slot, it takes pressure off the Wildcats quarterback, whether it’s Johnson or Hilinski.

“He’s playing at a really high level,” Fitzgerald said of Hull after the Ohio victory. “We’re gonna need him. If he continues on this path, he puts himself in the conversation to be an all-Big Ten level back.”

The question is now if Hull can carry this into B1G play, which starts back up Saturday evening at Nebraska. The real test will be in Weeks 9-11, when Northwestern faces the top 3 rush defenses in the conference: Minnesota, Iowa and Wisconsin. That’s where the passing game will need to improve.

But before then, the Wildcats will face the No. 12, No. 6 and No. 10 rushing defenses in the league, which could be opportunities for the run game — particularly Hull — to shine.

It starts with the trip to Lincoln against Nebraska, which has allowed the 3rd-most rushing yards in the B1G. Rutgers and Michigan follow. Fans can probably expect to see a lot of handoffs to Hull in those games.

Given how much Porter meant to Northwestern, Hull is doing a more than admirable job of replacing him as the face of the running game. Not to get too far ahead of ourselves, but we could see a year of Porter and Hull next season upon Porter’s return to the active roster. That could be quite the two-headed monster for the Cats.

But we need to stay focused on the short-term future. It’s not unfair to say the Wildcats don’t look like they’ll be competing for a B1G title again this year. Well, at least they haven’t done anything to tell us differently through non-conference play. They just haven’t shown the same dominance they did last year, particularly on defense.

The run game could’ve been a major weakness for the Cats after Porter’s injury. Instead, Hull has put it on his back and turned it into a strength.