Subban received a five-minute major penalty and a game misconduct for slashing Stone in the area of his right hand or wrist in front of Montreal's net midway through the second period of the Canadiens' 4-3 home victory.
Stone fell to the ice immediately and writhed in pain. He left the game and was examined by the Senators' medical staff, but later returned.
Stone's leaving the game was crucial because the NHL's rule 61.3 states that, in the case of a slash, "when injury occurs, a major penalty must be assessed."
Subban was visibly upset upon hearing that Stone was back.
After the game, Stone suggested Subban may have intentionally tried to injure him.
"Obviously it was a pretty big hack," Stone said. "It looked like he wanted to hurt me."
Senators coach Dave Cameron called for Subban to be suspended while hinting at potential retribution.
"I think it's quite simple — it's a vicious slash on an unprotected part of the body," he said. "You either do one of two things. I think it's an easy solution — you either suspend him, or when one of their best players gets slashed just give us five."