The 24-year-old, who cemented his place as a starter with some explosive performances down the stretch last season for the Packers, has been placed on the injured reserve list and will require surgery.
"I can come back from it and I'll come back full strength," a surprisingly upbeat Harris said.
"It's tough but I face the fact that something has got to be done and I am ready to go at it full strength. I'm not sure when I'll have it (surgery) but ... got to be done."
Harris, who rushed for 157 yards and two touchdowns on 34 carries in four games for the Packers last season, aggravated the knee injury that had kept him out of the first few weeks of training camp.
Friday's game against Seattle was the first on his return from the initial injury.
"I kind of knew it, but I didn't think it was going to be like season-over trouble," said Harris. "But it's for the best. If it's for the best and it's better long-term, then hey, I'm all for it."
Green Bay head coach Mike McCarthy had been a big supporter of the running back after Harris had locked up a starting job late last season.
"He's a young player I felt would be an impactful player for us on offense," McCarthy said of his hopes for the team's 2013 campaign. "It's a tough blow for him. DuJuan was a big part of my individual focus for the season."