The loss of Durant is really going to show up defensively. My guess is the Cavs will try to run Harden's and Irving's dicks in the dirt on defense, and force them to their bench.
I'm sure it makes sense medically to keep Durant out, and Nash played him too many minutes on Wednesday anyway. For all of Sexton's heroics on Wednesday, he actually played 10+ minutes fewer than did any of the Big Three.
But not having Durant also gives the Nets (and Nash) a little bit of an out if they somehow manage to lose to the Cavs again. The Big 3 losing two straight to the Cavs would be something that would raise a lot of eyebrows among Nets fans, and nationally.