According to the Washington Post, Backstrom was injured falling into the boards during a game Dec. 26. He was at the team's practice facility Tuesday, but watched teammates skate from a hallway.
Capitals general manager George McPhee could not give an update on Backstrom's health.
"There are some things we can talk about, some things we can't, and we can't talk about the fitness or health of any players until training camp," he told reporters.
Capitals captain Alex Ovechkin played with Backstrom in Russia and said his teammate was "a little dizzy."
Backstrom missed 40 games with a concussion last season after he was elbowed in the head by Rene Bourque, who was suspended five games for the incident.
"I think it's just a situation, you know, it's a contact game, it's a physical game," Ovechkin added. "Even in (the) KHL (Kontinental Hockey League) it's a very good level out there. Again, it happens. So nothing you can do."