Carolina general manager Jim Rutherford told the News & Observer on Wednesday that Ruutu -- who had 18 goals and 16 assists last season -- underwent hip surgery recently in Colorado and would be sidelined until April at the earliest.
"We're not sure how long he will be out," Rutherford told the paper. "Certainly through the regular season, if we play it. Maybe longer."
Rutherford added he did not know how Ruutu sustained the injury. The 29-year-old passed his year-end physical after last season.
"In August he started complaining about it," Rutherford said of Ruutu, who led the club with 151 hits. "He tried a number of things to rehab it, but it got to the point the doctors recommended surgery.
"There was really nothing that signaled surgery might be necessary. It just flared up. Like most athletes, hockey players have a lot of wear and tear on their hips."