According to Capfriendly the Sens are currently at the 23 man roster limit. Once Zaitsev and Hellberg clear waivers that will free up two roster spots. Zub will eventually take one of them but until he is activated off of LTIR that will leave two spots open.
These moves could potentially be done if the Sens are intending to call one or two players up and they wouldn't be able to officially call them up until Zaitsev and Hellberg clear. With Joseph listed as the extra forward in practice today and Gambrell listed in his spot that could suggest that the Sens are interested in calling up a forward or two.
There are likely only 4 forwards that would get consideration for a call up at this point and they are Cole Reinhardt, Ridly Greig, Egor Sokolov and Angus Crookshank.
The special teams have been an issue for the Sens so there are some options here.
Reinhardt is more of a 4th line option but he is a solid penalty killer, I'm inclined to think he wouldn't get as strong consideration for a call up if they are looking for someone who can play a middle six role.
Ridly Greig can be effective on both the penalty kill and powerplay. He would likely get serious consideration for a call up. The only thing that might make the Sens hesitant is that he hasn't played as many games because he was injured for a chunk of the start of the season.
Egor Sokolov is a solid option for the powerplay. He hasn't scored a ton of goals to start the season but he has been consistently putting up points. Troy Mann mentioned that he has been good defensively this season and his primary criticism is that he was playing too methodical and maybe a little too caught up in his head.
Angus Crookshank is another option for the powerplay. He had a good preseason but was playing more of a depth role in Belleville to start the season. He hasn't had as much experience at the AHL level and Troy Mann mentioned that he had some details he needed to work on in terms of his defensive play at that level.
Given the fact that Joseph was playing RW that favors Sokolov for consideration for a call up. Brassard also hasn't produced much at center so that could give Greig some serious consideration for a call up as well. Greig will likely have chemistry with everyone and Sokolov has had good chemistry with Pinto in the past. Maybe calling one or both up helps spark the team to a win.