Here’s the list of bad things that can happen when opponents leave Portland’s wings outside alone:
They might hit the shot.
That’s it.
Now here’s the list of good things that result from keeping an extra defender near the lane:
Shut off Lillard and McCollum driving angles
Force Nurkic to take longer making his post moves, increasing the chances he’ll turn it over
Stop momentum on the Nurkic-Lillard high pick and roll before it starts
Close off passing lanes
Crowd McCollum’s mid-range shot
Take away offensive rebounds, including those that might result from three-point wing misses
Lacking scoring depth, faced with extra defenders inside, the Blazers get forced into isolation ball. This is not as bad as it seems. Almost any shot from Lillard is preferable to the average attempt from scorers 4-12 on this team. But once upon a time the Blazers managed to generate quality attempts for their main scorers through crisp screens and decoy motion. As the supporting cast has been frozen out of the offense, their enthusiasm about participating in same seems to have waned.
We’ve already chronicled Portland’s horrid 4.1 point-per-game production on the fast break, a historically-low mark that trails the entire league by a wide margin
The Blazers rank 25th in the league in Points in the Paint, 27th in Points off Turnovers. Even though they’re 9th in offensive rebounds per game and offensive rebounding percentage, they rank 16th in second-chance points . They’re also down to 13th in the league in free throws attempted per game. A month ago they ranked 6th in that category.
When opponents have to pick and choose what to stop, you have a good chance of winning. When they can stop everything they want to and the rest doesn’t matter, your team’s in trouble. Against good defensive teams, this is starting to happen with regularity. The Blazers haven’t found a solution yet. Whether that’s tweaking the system or getting new players, they need to...and soon.
there's a lot more in that article if you want to read it
https://www.blazersedge.com/2017/12/8/16750382/trail-blazers-offense-stats-lillard-mccollum-nurkic-rankings