Sacramento Kings
Grade: D-
The best way to properly assess the value of players is by looking at past trades of players of similar caliber/contract. After all, front office executives (the people who participate in these trades) are the ones who create the market for these players.
For the sake of simplicity, we will call Grant a high level starter (aka a great role player). Those types of players generally warrant the equivalent of two first round picks (assume we are talking about two average first round picks, since all picks are not created equal).
However, we still need to factor in Grant's contract, which, in this case, diminishes his value. Grant is in the second year of a five-year, 160-million-dollar deal (per Spotrac). Even with the salary cap projected to increase over the next couple of years, that's still an average annual value of 32 million dollars for another four years for a player who is good (but not great) and on the wrong side of 30.
With that in mind, his value should be more like one or one-and-a-half first round assets plus whatever it takes to match the salary.
That brings us to the proposed trade. Here the Kings are parting ways with Kevin Huerter (a starter on a solid contract), their first round pick in this draft, and a future protected first round pick (which you assume will convey if they still have Grant under contract with the rest of their core).
That's the equivalent of three first round picks. And that's without even mentioning Trey Lyles (a solid bench player on a good contract), who could command one or two second round picks by himself on the open market.
Needless to say, the Kings are giving up way too much in that hypothetical trade. Here is what a better trade would look like for them.
(Sidebar: I did run this through a trade machine to verify that the salaries would work.)
Here, the Kings would be giving up Harrison Barnes (a starting caliber forward that could be flipped for more assets), Davion Mitchell (a reclamation project who has flashed some promise), and a late lottery pick in this draft.
All together, that is more like two first round assets, which is still a bit much, but way better than what was originally prescribed.