As it stands, the Sabres have three forwards remaining who came into camp vying for a roster spot: Derek Grant, Alex Nylander and Hudson Fasching.
Possibility 1: If both O'Reilly and Okposo begin the season in IR, it's possible that all three of Grant, Fasching and Nylander remain with one serving as the 13th forward.
Possibility 2: If one of O'Reilly or Okposo is able to play, the Sabres could still keep all three and scratch two (assuming they carry seven defensemen), but it's more likely they make a decision on who to send down. Grant's six-point preseason makes him a likely candidate to stay, leaving the two young forwards to choose from.
If Fasching was sent down, he'd report to Rochester. Nylander's situation is less clear - the Sabres can either send him to Rochester, which would give them the option of recalling him at a later time, they can send him back for another year in junior hockey in Mississauga or he can go play professionally in Sweden.
Possibility 3: If both O'Reilly and Okposo are ready to play on Thursday, one of Grant, Nylander or Fasching can remain and the Sabres will be set with 13 forwards.
Defense
Bylsma said he expects both Bogosian and Kulikov to play on Thursday, which leaves Ristolainen as the only uncertainty on defense. Ristolainen is currently a restricted free agent, but Bylsma said that he hasn't given up hope that a new contract can be agreed upon prior to opening night.
On Tuesday, the Sabres had seven defensemen on the ice: Bogosian, Kulikov, Jake McCabe, Josh Gorges, Cody Franson, Casey Nelson and Brendan Guhle. Bylsma said that the team will carry seven defensemen on their road trip in Western Canada, which begins on Sunday in Edmonton. If Ristolainen doesn't sign in time to play on Thursday, the Sabres appear set with those seven.
If Ristolainen does sign, the question of who sticks as the seventh defensemen remains. Guhle, a left shot, can play up to nine NHL games before the Sabres have to decide whether or not they want to send him back to junior hockey in Prince Albert. Once he's sent back, however, he's there for the remainder of the season, and Bylsma said that because of the finality of that decision (combined with his strong play recently), the Sabres will keep him as long as possible.
Nelson, a right shot, can be recalled from Rochester if he is sent down, but he may have made a compelling enough case in the preseason not only to stay on the roster, but to break into the top six and force a regular from last season into the seventh slot. Bylsma noted that possibility earlier in camp and lauded Nelson for his "commanding" presence on the ice.
Nelson skated on a pair with Kulikov in line rushes on Tuesday, with Guhle rotating in as the extra defenseman.