The 26-year-old forward could have become an unrestricted free agent at noon ET.
"Number one, [Girgensons is] a player who truly executes within the framework of what we need defensively, and he is a threat to score," Sabres coach Ralph Krueger said in September. "… And he always works 100 percent from the start to the end of practice, so that gives him quite a consistent game during the games. You know exactly what you're getting from him shift in and shift out. A very important body in our group."
Girgensons scored 19 points (12 goals, seven assists) in 69 games with the Sabres last season.
Selected by Buffalo in the first round (No. 14) of the 2012 NHL Draft, Girgensons has scored 138 points (61 goals, 77 assists) in 489 regular-season games over seven seasons, all with the Sabres.
