The Hurricanes, who lost in the Eastern Conference's second round and went into the offseason in the market for more veteran scoring, acquired the 33-year-old Pacioretty in July from Vegas for future considerations due to the Golden Knights' salary-cap crunch.
The six-time 30-goal scorer filled a need for a team looking for more output to a forward group led by young talents Sebastian Aho, Andrei Svechnikov and Teuvo Teravainen, but the injury will delay those plans for a franchise considered one of the favorites in the Metropolitan Division.
The Hurricanes did not provide any details on how or when Pacioretty was hurt. Messages left with the team and Pacioretty's agent from The Associated Press were not immediately returned.
Earlier in the day, Carolina announced it had re-signed another veteran forward, Martin Necas, to a two-year, $6 million contract.
The contract will pay the 23-year-old Necas $2.5 million next season and $3.5 million for the 2023-24 season. That keeps the young forward with the franchise that selected him in the first round of the 2017 draft and ensures some depth behind the aforementioned top liners.
Necas relies on his speed and skill, and he often takes advantages of mismatches going up against the opposition's bottom-two lines. He was inconsistent last season, however, while finishing with 14 goals and 26 assists. In the playoffs, during which Carolina defeated the Boston Bruins in Round 1 before falling to the New York Rangers in Round 2, he couldn't find the net in either series.
"I've got to help the team more, got to produce way more," Necas said in June after the Hurricanes were eliminated. "That's what everyone kind of expects from me. I didn't do it this year, so, like I said, it was disappointing for me."
Still, Carolina is betting on Necas' long-term potential.
"We've got to find a way to punch through [in the playoffs]," Hurricanes coach Rod Brind'Amour said in June, "and I think Marty obviously has the potential to help us do that."
Necas, who was a restricted free agent, has 45 goals in 203 NHL games with Carolina.
The Associated Press contributed to this report.