Subban, 27, has not played a game for the Blackhawks this season after appearing in 16 in 2020-21.
The 2012 first-round pick has played in 82 career NHL games and posted a .899 save percentage. He is currently on the final season of a two-year, $1.7 million deal.
Friedman stated in his latest 32 Thoughts blog that the Sabres were "definitely looking for an upgrade" in net.
Dustin Tokarski, Aaron Dell and Craig Anderson have split the load between the pipes for Buffalo so far this season. In 14 games, Tokarski has a .903 save percentage while Dell has a .862 save percentage in five appearances. Anderson, 40, began the season well with a .921 save percentage but hasn't played since Nov. 2 due to an upper-body injury.