Mistakes cost Northwestern in loss to Michigan State

A fumble seemed to change everything.

With the score tied at 3 in the second quarter Saturday at Ryan Field and Northwestern in the midst of a 60-plus-yard drive that started at its own 35, it appeared the Wildcats were poised to take a 10-3 lead on No. 11 Michigan State. It was up to freshman running back Treyvon Green to get the job done.

But after Green plowed through the Spartans’ line and appeared to be down near the 3, the ball popped out of his hands.

That led to an eight-play, 97-yard drive by Michigan State that ended in Le’Veon Bell’s seven-yard touchdown run in which he faked out cornerback Daniel Jones heading into the end zone.

That was all the Spartans needed as they rolled to a 31-17 victory, snapping the Wildcats’ four-game winning streak.

NU (6-6, 3-5) did get to within a touchdown twice, once to start the third quarter and again to start the fourth. But the Wildcats’ woes came down to missing Jordan Mabin on defense. The cornerback injured his right shoulder in the first quarter and was replaced by Jones, a redshirt freshman.

‘‘I was extremely disappointed for Jordan in his last opportunity to play in Ryan Field, to get dinged up where he couldn’t play anymore,” coach Pat Fitzgerald said.

Jones proved to be a liability, getting beat on the Bell touchdown and then twice by B.J. Cunningham (six catches for 120 yards) on his two touchdowns.

Fitzgerald didn’t blame Jones for the blown coverages and said he had earned the right to play this week based on how he did in practice. Linebacker Bryce McNaul said the defense didn’t have to readjust much with Jones subbing for Mabin.

‘‘I’d like to say it was backbreaking, but we’re confident in the depth we have on defense, especially at other positions,” McNaul said. ‘‘You can’t afford to think about what’s going on somewhere else, and you have to focus on your job.”

There was still that elephant in the room: Green’s fumble.

When Michigan State (10-2, 7-1) started its possession after the fumble, Fitzgerald took a timeout to give his staff in the press box time to figure out if the fumble call should be challenged. They said no, and Fitzgerald didn’t challenge. Green never got back into the game.

On their next possession, the Wildcats had the ball at their own 23 on a fourth-and-11 with 48 seconds to play in the half. Instead of letting the clock run out, they punted, and Keshawn Martin returned it 57 yards for a touchdown.