The Blackhawks shut out NHL-leading St Louis 4-0 but not before losing their star forward after Blues forward Brendan Morrow landed on Kane's left leg in the second period.
Kane fell awkwardly and remained on his hands and knees before slowly skating to the bench.
"It's definitely a huge loss for us," said Blackhawks coach Joel Quenneville, who was noncommittal about when Kane might return.
"Certainly he's a special player and we'll have to work our way through it, knowing what he brings to our team."
Kane has 29 goals and 39 assists on the season for a team-leading 68 points.
Chicago's (40-15-15) win Wednesday pulled them into second place in the Central Division, six points behind the Blues (47-15-7).
(Writing by Jahmal Corner in Los Angeles; editing by Sudipto Ganguly)