LTIR provides cap relief for the time the player is on LTIR, the player doesn't come off the cap, you just get a pool of cap relief that can be used while the player is on LTIR, it's use it or lose it.
Technically it makes things a bit tighter for us once Chabot comes off LTIR, because without LTIR, we were accumulating unused cap space, albeit not much since we were so tight to the cap. When we placed Chabot in LTIR, that accumulation halts, and instead of drawing against it when we call someone up, we draw from the relief fund. So we'll lose the prorated accumulation of 4 weeks of 120k in capspace.