Sophomore running back Cheng Ho scored twice in the Crimson’s victory at lowly Columbia last week. He faces a tougher task this weekend against a tough Penn defense that has allowed only 2.7 yards-per-game. But the Quakers, one of the top teams in the lea

What happens when the immovable object meets the…well, immovable object?

The answer will be learned tomorrow, when Harvard (6-2, 5-0 Ivy) meets Penn (3-5, 2-4 Ivy) at Harvard Stadium at 12:30, pitting two of the top defenses in the Ivy League.

Both offenses will have to work to move the ball, as the two squads are in the top three in the league in all but two of the defensive statistical categories kept by the league office. Penn, after a difficult beginning to the season, held Yale to just 13 points in regulation, the lowest output by the undefeated Bulldogs this year, before dropping a 26-20 decision in double overtime, and is holding opponents to just 2.8 yards-per-carry, second only to Harvard’s 2.7.

“They’re as good as any defensive team in our league,” Harvard head coach Tim Murphy said. “Here’s a team that held Yale to one touchdown in regulation and shut out Princeton? I’ll tell you what, we better be ready to play because they’re a good football team.”

Penn’s offense, meanwhile, has struggled mightily in the switch to a spread attack of new offensive coordinator Bill Schmitz. Other than a 59-point outburst against Columbia and 42 points against Dartmouth, the two weakest defenses in the Ivies, the Quakers have scored 17 points or fewer in every game, including two games with just seven points.

Further complicating matters was the season-ending injury to starting quarterback Robert Irvin, one of the league’s top returning passers, early in the year, leaving backup Bryan Walker as the starting man for the remainder of the season. Walker, a more mobile quarterback, has thrown for 1,265 yards, eight touchdowns and seven interceptions so far this year, while also running for 162 yards.

“We’ve been erratic,” Penn head coach Al Bagnoli said. “We’ve had to tailor the offense for the second quarterback. One of the assets that Bryan has is his speed, so we’ve tried to get him out of the pocket on bootlegs.”

The real strength of the Penn offense, however, is a healthy Joe Sandberg. The senior running back has been slowed by injuries all season, missing parts of over half of the Quakers’ contests this year and sitting out a loss to Villanova entirely. Despite the injuries, Sandberg has run for 793 yards and nine touchdowns on the year, both second in the league to Yale’s Mike McLeod.

“He brings the elements of vision, balance, escape ability, and speed,” Bagnoli said. “You just never replace a great, great player [in your lineup].”

For the Crimson, the challenge of moving the ball on a stiff Penn defense will fall to sophomore running back Cheng Ho, who earned his second and third career 100-yard rushing games the last two weeks, and senior quarterback Chris Pizzotti, who leads the Ivies in pass efficiency. Harvard, also leading the league in turnover margin, will have to avoid turnovers against a Quakers team that is forcing almost three-per-game.

“We’re going to have to play a great field position game,” Murphy said. “We’re going to have to be very patient, and we’re going to have to take care of the football, as we have, because this is a team that can beat you.”

For the Crimson, the game is also loaded with Ivy League implications. Last weekend’s win over Columbia assured that Harvard will play for at least a share of the Ivy championship when it arrives at Yale for The Game on Nov. 17. A Crimson win tomorrow, coupled with a Yale win over Princeton, would make The Game a de facto championship game, while a Bulldog loss would guarantee Harvard at least a share of the crown.

Murphy and the players are well aware of the mounting pressure.

“The minute you try to say it’s just another game, you’re not being honest with yourself or the players,” Murphy said. “The pressure mounts, the intensity mounts, but that’s why we play the game.”

—Staff writer Brad Hinshelwood can be reached at bhinshel@fas.harvard.edu.