Hampton backed up Doak Walker Award-winner Shonn Greene last season and rushed for 463 yards and seven touchdowns. Projected to succeed Greene as Iowa's starting tailback this fall, Hampton injured his right knee in July during voluntary workouts.
The injury was originally feared serious, but Hampton returned for the start of preseason practice, only to suffer a setback about a week into camp. Ferentz told ESPN.com last week that Hampton wouldn't play in Iowa's opening game and said it was possible the injury could be season-ending.
That possibility is now a reality, and Ferentz confirmed Hampton will need knee surgery.
"We obviously thought he had a chance to make it back," Ferentz said. " . . . He was doing things that were heavy-duty football things, and unfortunately the episode that tipped him over the balance was hardly of that category. He's been in a lot more strenuous exerting positions. It's just one of those things and it can happen to anybody. But certainly it's just unfortunate."
Hampton will use his redshirt year for the 2009 campaign and have three seasons of eligibility remaining. Without Greene -- taken by the New York Jets in this year's NFL draft -- and Hampton, Iowa loses 94.2 percent of its rushing production from last season.
Former walk-on Paki O'Meara will get the start at running back Saturday against Northern Iowa, with redshirt freshman Adam Robinson serving as his backup. O'Meara had 21 carries for 62 yards and two touchdowns last year.
Redshirt freshman Jeff Brinson has returned to practice after battling an ankle injury, but likely won't play Saturday.
"Brinson's making progress," Ferentz said on the Big Ten coaches' teleconference. "Problem there is he's missed a lot of time, so he's way behind."
Adam Rittenberg covers Big Ten football for ESPN.com. He can be reached at email@example.com.