Considering the situation right now, it is extremely unlikely that the habs accrue any extra cap space from now until the end of the season. Without making a trade, the maximum they could accrue is $423 every day Byron is sent down when the team is fully healthy (other than Gallagher), and assuming they don’t add another roster player at the deadline.
Assuming again full health (other than Gallagher), and that the habs don’t trade away anyone, the absolute maximum extra cap space the habs could accrue is $68,197 after the deadline, and that’s if they traded for a players at league minimum, who was retained 50% by two different teams and Romanov & Byron were sent down on off-days. This is obviously not going to happen, so it’s safe to say that the habs will have $376,322 in accrued cap space at the end of the season, as long as they don’t exceed their LTIR cushion (which is $85,140,399).
Now the team below has $2,724,090 in space between them and the limit that Gallagher’s LTIR allows them to approach. That is likely the extent of a contract that the habs will/could add at the deadline. And injuries won’t be a problem, since Primeau/Evans/Leskinen can be called up as emergency exceptions and not count against the cap if Armia/Chiarot/Price are still out. Now the habs could dip into their accrued cap space pool if they really wanted to, which would give them an extra $1,616,792 in deadline cap space, and $4,340,882. However, I doubt the habs would need that much cap space to make any move, and it would also result in an extra $376,322 in performance bonus overages for next season.
Now concerning next year, the habs are well on their way to having at least $637,500 in performance bonuses this year (Romanov Top-4 in D TOI, Suzuki & Kotkaniemi Top-6 in F TOI). If the minimum assist total bonus is included in Suzuki’s contract and he keeps up his current pace of at least 24 assists, that would add another $212,500 to the performance bonuses. Also, if Kotkaniemi somehow ended up in the top 3 in forwards on the team in +/- it could increase by another $212,500, but that’s extremely unlikely. Also, Cole Caufield could earn a $25,000 bonus for playing 7 NHL games, and another $107,500 for playing 14 games. So considering all this, Montréal’s total performance bonuses could range from $637,500 to $982,500 at most. Assuming the habs don’t accrue anymore cap space, this means that they’ll have from $261,178 to $606,178 in performance bonus overages for next season.
I’ll leave the link to my spreadsheet in the comments.
By the way, the list of people sent down/called up is based on the opening night roster + Perry (and later with Staal as well).