Per Adrian Wojnarowski:
Sources on @TheVertical: Portland sends Denver center Mason Plumlee and '18 2nd-round pick for Jusuf Nurkic and '17 first-rounder (via Griz)

Plumlee is an upgrade over Nurkic, but Denver still isn't beating Golden State or San Antonio in the first round, that is if Denver holds on to a playoff spot. And they'll have to offer a max contract to Plumlee or else he'll walk after the season. Is that worth a '17 first-rounder, even if it's a low first-rounder, for a team that still needs to build up assets?