Schwartz, 23, sustained the injury on Friday after he slipped and slid into a goal post during practice. The team said they will re-evaluate Schwartz in 12 weeks and have placed him on injured reserve.
Schwartz has recorded four assists in seven games so far this year. Last season, he played in 75 games, posting 28 goals and 35 assists.
St. Louis is also missing forward Paul Stastny, who will be out at least five weeks with a broken foot. Another Blues’ forward, Patrik Berglund, had right shoulder surgery back in August and is expected to be out for four months.
The Blues play the Islanders on Sunday.
- Beth Maiman