NBA Projections 7/7/17 and a word on 2018
It's worth starting to look at that 2018 figure now.  At the start of 2017 free agency, the total around the league was about $400 million. (Obviously, more than that in contracts can be signed due to exceptions.)  So next year it's $488 million, and that doesn't include the effect of any further multi-year contracts signed this year, any rookie extensions, or any veteran extensions (which are now more palatable than under the old CBA).  So yes, that 2018 market is looking pretty tight, although there are fewer big name free agents next year as well.