Montreal's Walter Spencer, right, is in hospital following an altercation at a bar on the weekend.

Alouettes linebacker Walter Spencer was taken to hospital early Monday with serious injuries after what police sources say was a stabbing at a Montreal bar.

Team officials said only that Spencer was involved in an incident without revealing the extent of his injuries or how they occurred.

But sources with Montreal police told SRC, CBC's French-language arm, say a man was stabbed in the upper body during a fight in a bar on St. Laurent Boulevard.

A CFL source who requested anonymity told The Canadian Press that Spencer got into an argument with another person when he was "attacked" and stabbed twice, including in a lung.

The source called it a "blindside" attack that Spencer did not see coming and that he was lucky not to have been killed.

Following surgery, Spencer was listed in stable but serious condition.

The 31-year-old Detroit native currently leads the Montreal Alouettes with the most special-team tackles this season. He's played seven seasons in the CFL, including stints with the Saskatchewan Roughriders and the Calgary Stampeders.

With files from The Canadian Press