At the time, it was unclear what was wrong with Markov. All that was being reported was that he could not walk on his own, and had to be lifted into the Canadiens' dressing room.
It is now being reported that Markov sustained an injury to the lower part of his left leg, specifically his ankle.
According to sources, Markov suffered the injury when his ankle was slashed by the skate of teammate Carey Price on Toronto's third goal.
Markov did not get on the bus to Buffalo with his teammates for their next game Saturday night against the Sabres. Instead he will stay behind and spend the night in a Toronto hospital for examination and treatment.
Update: According to Sportsnet, the injury to Andrei Markov could be serious. They say that he may have suffered tendon damage and could require surgery. If that is true, Markov would likely be out for months.
2nd Update: Team 990, a sports radio station out of Montreal, has just reported that Andrei Markov was operated on last night in Toronto to repair the damage in his leg. Based upon these reports, and considering that it is being reported that it is tendon damage, Markov would likely be out until around the All-Star break. Though nothing has been confirmed as of yet by the Montreal Canadiens.
3rd Update: Sportsnet is confirming that Andrei Markov did have surgery overnight in Toronto to repair tendon damage. They say that he will likely be out for 2-3 months.
4th Update: It's official. Read my article here explaining exactly how long Markov will be out and what this means for the Habs.