With the consensus (here, here, and here)being that the Buffalo Sabres have their top 4 defenseman set: Zach Bogosian, Rasmus Dahlin, Rasmus Ristolainen, and Marco Scandella; there will be 4 defenseman battling for the final 2 spots in the lineup.
Due to injuries, instability, and overall poor play the Sabres had a revolving door at defense last season. 11 defenseman played more than 10 games with 2 more defenseman getting ice time. That can be contrasted with the 8 defenseman that suited up for the Sabres the last time the team made the playoffs.