Forward Christina Julien is out after colliding with an opposing player in the dying seconds of Canada's 6-0 win over Haiti in the opening game Thursday.
Julien sat on the field receiving treatment from the medical staff afterwards while her teammates went to celebrate with the fans.
"She may have suffered a concussion and that could be a problem for us," head coach John Herdman said at a team practice Friday.
"We're just managing that at this moment in time. If it is, she could miss quite a few games, which is a real shame because she's been in real white hot form so we've got to wait and see on that."
Meanwhile, midfielder Lauren Sesselman is also expected to miss Saturday's game against Cuba after injuring her knee against Haiti.
Sesselman appeared to hyper-extend her left knee near the end of the first half and there's still no indication as to the extent of the injury.
Herdman said prior to the tournament that he expected the roster to rotate with potentially as many as five games in 11 days.
The busy schedule means Herman will have to rest Christine Sinclair — the focus of Canada's attack — at some point.
Sinclair, who scored four goals for Canada against Haiti, knows she'll need to be fit and ready to go for the possibility of next week's semifinal, which will ultimately decide whether or not Canada qualifies for the London Games.
"Ultimately, I think everyone at this level wants to be on the field but in a tournament like this there's a bigger picture," said Sinclair.
"It's about trying to be fresh come that semifinal game and I think all of us as players respect (Herdman's) decisions whatever they may be."
Canada's final game of the round-robin portion of the tournament comes Monday against Costa Rica. The top two teams in each of the two groups advance to the semifinals next Friday.
The winners of the two semis games advance to the Olympics.