Garon departed four minutes into the first after making a save. He appeared to get hurt when he kicked his leg out on the play.
Lightning coach Guy Boucher said Garon will have an MRI on Wednesday.
"He's been playing well for us," Steven Stamkos said of his teammate. "It was tough."
Dwayne Roloson replaced Garon, who had gone 12-3-2 in his previous 17 starts.
Information from The Associated Press was used in this report.