No. 4 Michigan got severely shaken and seriously tested Saturday at Indiana.

First, beloved running backs coach Mike Hart was carted out of Memorial Stadium with a health scare, and then the 22.5-point underdog Hoosiers traded blows evenly with the Wolverines in a first half that ended tied at 10.

It took a reassuring message from Hart, being treated for a seizure at a nearby hospital, and a 98-yard drive after the break to get Michigan back to its steady, dominant self. Even then, the Wolverines couldn’t shake the Hoosiers easily.

Eventually, Michigan (6-0, 3-0 B1G) did wear down Indiana (3-3, 1-2), finally taking a 2-score advantage just inside the 10-minute mark of the fourth quarter and continuing on to a 31-10 victory.

JJ McCarthy, Blake Corum and Ronnie Bell — key players on Michigan’s offense — all delivered big plays on the 11-play march that gave the Wolverines the lead for good. McCarthy, who took over the starting QB job in Week 2, hit Bell for a 3rd-down conversion after Cornelius Johnson dropped a perfect pass to leave Michigan backed up near its goal line. Corum, bottled up on all but 1 carry in the first half, busted an 18-yard run. McCarthy took off around the left edge to convert a 3rd down. To end the drive, McCarthy rolled right and found Johnson for a 29-yard catch-and-run touchdown.

McCarthy, the 5-star 2021 recruit who replaced Cade McNamara as QB1 in Week 2, threw his 1st interception of the season in the second half but recovered to hit tight end Luke Schoonmaker for a 9-yard touchdown that finally gave the Wolverines a 2-score lead.

McCarthy finished with a season-high in passing yards, eclipsing 300 yards for the 1st time as a Wolverine. He threw for 3 TDs.

Corum had his 3rd straight 100-yard rushing game, finishing with 124 yards and a TD on 25 carries.

Bell also had his most productive game, 11 catches for 121 yards.

The defense pitched a second-half shutout and racked up sacks and QB hurries.

The first-half scare

McCarthy completed his first 8 pass attempts. Corum went 50 yards on his first carry to set himself up for the game’s opening score, a 1-yard run.

But Indiana wouldn’t fold. Even with no ability to run the ball, the Hoosiers parlayed an up-tempo, no-huddle offense into 2 sustained drives and 10 points.

Meanwhile, the defense — without injured leading tackler Cam Jones and all-B1G corner Jaylin Williams — stiffened after Michigan’s opening salvo. A 4th-down stop late in the half put an exclamation point on the turnaround.

Michigan went to the locker room knowing it was in a B1G East fight.

Through 30 minutes, Indiana quarterback Connor Bazelak was outproducing McCarthy. Bazelak had thrown for163 yards and a TD, going 18-of-31 while getting sacked 3 times and picked off once. McCarthy extended his 100-plus-pass streak without an interception, but hit on only 5-of-10 throws after the hot start. He entered the 2nd half with 129 yards, a long connection of 29 yards and no TDs.

Michigan saw Trente Jones carted off the field in the 2nd quarter after Hart left in the 1st quarter. The word at halftime was that Hart had a seizure. Hart served on Indiana’s staff from 2017-2020, so both sides felt deep concern for the former standout Michigan running back.

Beyond those worries, Michigan faced the prospect of its first loss, which would be a major blow to its hopes to return to the College Football Playoff and raise a lot of questions ahead of No. 10 Penn State’s visit to Ann Arbor next Saturday.

What worked for Indiana

Indiana held Corum to 10 yards on 9 first-half carries after his initial 50-yard burst.

Using its up-tempo game plan, Indiana went 76 yards on 10 plays in 2:46 to answer Michigan’s opening-drive score. It went 52 yards on 12 plays for a field goal that answered one by the Wolverines.

By the end of the third quarter, Bazelak had thrown 40 times, completing 23 for 190 yards. The Hoosiers led in first downs, 20-18, entering the final 15 minutes. Emery Simmons was Bazelak’s favorite target, with 7 catches for 57 yards. Cam Camper, the team’s leading receiver entering the game, had just 2 catches through 3 quarters.

Michigan’s relentless pass rush eventually won the day. Bazelak had been sacked 5 times and pressured 22 others with 13 minutes still remaining in the game.

The fallout

Indiana lost its 3rd straight game and 26th in the last 27 meetings with Michigan. The Wolverines pressure cooled off Bazelak, who entered as the B1G’s lowest-rated starting quarterback. Because of injuries, the Hoosiers were without receiver DJ Matthews Jr. and tight end AJ Barner.

As for Michigan, it played without key receiver Roman Wilson, injured last week. TE Erick All and McNamara remained unavailable.

Up next for Michigan

The Wolverines host No. 10 Penn State (5-0, 2-0), the first time either team will be facing a ranked opponent this season. The programs haven’t had a top 10 showdown since the 1990s, so FOX’s Big Noon Kickoff will have a game worth hyping. The Lions will be well rested coming off a bye.

Up next for Indiana

The Hoosiers will remain at home and remain underdogs when they face B1G East rival Maryland at 3:30 ET next Saturday (ESPN2). Taulia Tagovailoa and the Terps (4-2, 1-2 after Saturday’s 31-29 loss to Purdue) have an almost 80% chance of winning, according to ESPN’s matchup predictor.