Ryan O'Byrne of the Montreal Canadiens is expected to be out for a number of weeks after suffering a knee injury in Saturday's road victory in Buffalo. (Phillip MacCallum/Getty Images)

The Montreal Canadiens will have trouble icing a team in a few weeks if the current pace keeps up, after they reportedly lost their second defenceman to long-term injury in as many games.

Ryan O'Byrne was injured during Montreal's 2-1 victory over the Buffalo Sabres on Saturday night. French sports network RDS reported on Sunday that O'Byrne has a knee sprain that will keep him out approximately six weeks.

The big defenceman was expected to play a greater role with the NHL club after playing a total of 70 games over the previous two seasons.

The Canadiens lost all-star defenceman Andrei Markov in Thursday's season opener in Toronto. Markov suffered a lacerated tendon in his ankle and is expected to be out for about four months.

The Canadiens announced on Sunday that defenceman Yannick Weber, 21, has been recalled from their Hamilton affiliate in the American Hockey League.

Weber impressed in the pre-season and was among the final cuts. The native of Morges, Switzerland, appeared in three games for Montreal last season, recording an assist.

While Weber is small for a defenceman, at five-foot-11, he boasts a good shot from the point and scored 16 goals and 28 assists for Hamilton last season.

The Markov injury had reports circulating that recently longtime Canadien Patrice Brisebois would be willing to put off his recently announced retirement.