You can't bank it, but you can front-end contracts, which is what they'll likely do if Nikorima and/or Roberts go. It's likely we already have some space this year with McGuire & Kahu going, so let's just say we have $1 million left free this year. What we do then is, instead of having to compete with the Roosters for a 2 year, $750k/yr deal for TPJ, we sign him for $600k a year but "upgrade" this year's contract with an extra $300k. TPJ gets the same amount in total, but it's less load on our future cap.
Apparently, this is what the Roosters are good at (if you believe they aren't blatantly cheating anyway). Being able to fire underperforming players because of convenient drug tests helps of course, but they use any breathing space to front-end contracts of their best performers, so when, say, a Cronk comes along, they have the room to sign him.
It also explains why they often fluctuate anywhere from the bottom of the ladder (15th in 2016) to the top (2nd in 2017, equal first in 2018). They're happy to cop a couple of shitty years in order to stack their roster for a short premiership window.
