Looking again at that breakdown, I'm actually even more optimistic. Boston's roster is the most complete and competitive among the teams with Starting Cap Space.
With nearly $13 mil -- without having to jettison any rostered players, cap holds, or draft picks -- Boston can potentially add a very good piece in FA before Ainge begins to work out trades for further roster improvements.
Right, and we practically speaking have much more cap space (or it won't matter). Firstly, Spotrac, who's numbers this article used, is wrong about cap space, because they have a hold for Zoran Dragic, whom we released. So that brings us up to $15 million. Secondly, that $15 million includes cap holds and salaries for 17 players. We can't sign any free agents (or it makes little sense to do so, I guess) with 17 players on the roster. Getting down to 14 roster spots and cap holds probably means letting Zeller walk, drafting a foreign player, and releasing whichever of Amir and Jerebko you're replacing with a new free agent, or sending James Young away and giving up a 2nd rounder to do so (which is a trade I expect on draft night). Say, for example, we ditch Young, let Zeller walk, and use our own 1st on a foreign player who has no effective cap hold -- that brings us up to $24.5 million in cap space with our current roster minus Young and Zeller, plus two lottery picks (as of today).
It's very easy to see this team making some sort of improvement through free agency next summer, and the worst case scenario is we bring back virtually this same team with two high draft picks and a useful free agent signed to an Amir/JJ structured deal. Meanwhile, we have all kinds of tradeable contracts and assets as Danny keeps waiting for the right deal. And if he doesn't find one, it's still a team that challenges for 50 wins and gets yet another lottery pick from Brookyln, and then has even more cap room next summer ($60+ million with 10 players under contract already) to spend in what could be a monster free agency class. That's about the worst-case scenario. I can only get so disappointed thinking about this future.