Rendulic sustained the injury during Thursday night's game against the Florida Panthers.
The 22-year-old rookie recently became the first Croatian-born player to score an NHL goal after being recalled for the second time from Lake Erie on Dec. 31.
Avalanche coach Patrick Roy said that Rendulic will be out for "at least eight weeks," according to the Denver Post.
"It's sad, but I guess it's part of the game," Roy said. "We were excited about making [Rendulic, John Mitchell and Dennis Everberg] the third line for us. The couple of shifts they had together, there was size, there was speed. I really would love to see that happening because I thought it would be a great experience for these guys."
In 11 games this season, Rendulic has one goal and one assist.
The Avalanche (19-17-9) play the Tampa Bay Lightning on Saturday.
- Molly Geary