Michigan's defense has been one of the best in the nation this season, but the unit is going to have to play at its best against No. 2 Penn State on Saturday night when it will try to contain do-everything running back Saquon Barkley.

"It'll be a team effort defensively to go against a great player," Wolverines head coach Jim Harbaugh said Monday at his weekly news conference, "and a really outstanding offense – really good quarterback, good receivers, line and backs that are hitting on all cylinders. So I think our guys are excited for that task."

Despite returning just one defensive starter from last season, the 19th-ranked Wolverines (5-1, 2-1 Big Ten) are No. 1 in FBS in total defense (223.8 yards per game), opponents' third-down conversions (20.5 percent) and pass efficiency defense (opponents are completing just 44.1 percent of their passes).

They also are in the top 10 nationally in pass defense (138.0 yards per game, third), rush defense (85.8 yards per game, sixth), sacks (20, tied for sixth), and scoring defense (14.7 points per game, eighth).

In Saturday's 27-20 overtime win over Indiana, Michigan did not allow the Hoosiers to record a first down on six consecutive second-half drives. In six games this season, its defense has forced opponents to punt 52 times.

The defense will challenge a Penn State offense that is averaging 39.7 points and 456.2 total yards per game. The catalyst is Barkley, a 230-pound junior who has rushed for 649 yards, scored nine touchdowns and ended an idle weekend for the Nittany Lions (6-0, 3-0) having regained the FBS lead in all-purpose yards at 217.0 yards per game.

"He can catch the ball out of the backfield," Harbaugh said of Barkley. "He can run all the assortment of runs inside the tackles and on the edge, a very good pass protector. He is a multipurpose back that can do everything well."

One high-impact player for the Wolverines is 6-foot-5, 281-pound sophomore defensive end Rashan Gary, who starred against Indiana with 2½ tackles for a  loss including one sack. Harbaugh said Gary has overcome special attention from opponents trying to keep him from being a disruptive force.

"I've been saying it for a couple of weeks now – Rashan's gotten doubled, he's gotten chipped, he's gotten cut," the coach said. "Probably the ultimate compliment you can pay to a football player is to have that much concern about one guy and then having that type of game plan. So he's earning that kind of respect."

The Wolverines will be an ultimate test for Barkley, who, after rushing for a career-high 211 yards against Iowa, picked up just 56 yards on the ground against Indiana and 75 versus Northwestern. The matchup will be one to watch for the "White Out" sellout crowd at Beaver Stadium.

"I'm excited about it," Harbaugh said. "Talk to the players, I feel like they would feel the same way, excited for the opportunity. They've been on the big stage already this year multiple times in big games and have another crack at it. Knowing our guys the way they do, they're competitors, so I would feel they'd be excited."