EVANSTON, Ill. (AP) — Treyvon Green made his case to be moved up on the depth chart for No. 17 Northwestern.

Green rushed for 158 yards and two touchdowns, quarterback Kain Colter ran for 106 yards and a score and passed for another, and the Wildcats beat Western Michigan 38-17on Saturday night.

With starter Venric Mark, who missed his second straight game with a lower body injury, sidelined, Northwestern was just as explosive with Green — who is the Wildcat's No. 3 running back.

"I think it speaks to our depth," Colter said. "We have guys behind some of the starters that can play. When they get an opportunity like Treyvon did, they take advantage of it. Honestly, the competition makes the whole team better.

"Trey's made an argument that when (Mark) comes back, he should be in that starting role."

Northwestern had 474 yards of total offense — including 335 on the ground — to extend its winning streak in non-conference home games to 15. The Wildcats (3-0) averaged 46 points and better than 500 yards in their first two games against California and Syracuse.

Western Michigan (0-3) was led by quarterback Tyler Van Tubbergen, who was 16 of 41 for 202 yards with two touchdowns and an interception.

"We had some opportunities, but we just didn't make enough plays," Tubbergen said. "Credit to them. That's a pretty good team."

Despite starting its first three drives in WMU territory, Northwestern trailed 3-0 following the first quarter and couldn't get much going offensively.

"We have to get more consistent," Wildcats coach Pat Fitzgerald said. "We can't have games where we take 15 minutes off."

The Wildcats finally got going when safety Ibraheim Campbell intercepted Van Tubbergen at the Northwestern 43 — his fifth straight game with pick.

Northwestern needed just seven plays to cover the 57 yards, with Colter running the ball in from four yards out to give the Wildcats a 7-3 lead.

Western Michigan needed only one play to retake the lead at 10-7 when Van Tubbergen and freshman wide receiver Corey Davis hooked up on a 75-yard scoring pass. Davis made a cut as if he were running an out and then turned the route up field, fooling cornerback Dwight White.

That play did little to quell the offensive rhythm Northwestern established on the previous series. After starting their next drive on their own 35, the Wildcats covered 65 yards in six plays, culminating in Colter's six-yard touchdown pass to Christian Jones.

That score kicked off a stretch in which Northwestern scored 24 consecutive points. The Wildcats reached the end zone on their final four possessions of the first half.

A four-yard dash by running back Mike Trumpy made it 21-10 with 2:15 remaining in the half before Northwestern got the ball back with 51 seconds remaining before the break and moved downfield to set up Jeff Budzien's 35-yard field goal and 24-10 lead.

The Wildcats kept at it in the third quarter with an 87-yard, 14-play drive that ended with the first of Green's two touchdowns — a one-yard run that gave Northwestern a 31-10 lead.

Western Michigan finally snapped its scoreless string when Van Tubbergen and receiver Josh Schaffer hooked up on a 25-yard touchdown pass late in the third quarter to make it 31-17.

Northwestern answered on its next possession when Green had a 42-yard touchdown run to restore the three-TD lead.

For Green, a junior, it was a long road to get to that point where he's busting through with big scoring runs.

"It's been a little rocky, honestly, the season I had last year and issues with my family and coaches telling you you needed to lose weight and it's for the better," he said. "They kind of sprung that on me. Handling that and handling my family issues, it was an intense road.'"

Fitzgerald credited Green's play.

"I think Trey's been really solid during the first three weeks of the season, I've been really impressed by him," Fitzgerald said. "It was a very difficult year last year coming off the injury in training camp. He's looking like the faster, stronger, more explosive Trey Green that played for us as a freshman. I'm incredibly happy for him. He's a young man that's worked very hard to overcome adversity and he's from a great family. You love seeing great guys have success. I'm really happy for him."

Mark hasn't played since the opener against California and there's no telling when he might return.

"He's day-to-day, improving every day, feeling better every day," Fitzgerald said. "He's impatient. We're taking a long-term smart approach that when he does come back, he's 100 percent and ready to go. We're trying to be smart."

If Mark is smart, though, he'll get back soon to limit Green's carries.