A post up scoring threat off the bench.
I know a lot of people hate when I post some numbers, but I'd say this situation calls for it:
* 29.5% of Melo's offense comes from post-up. He ranks in the 55th percentile, so about 45% of NBA players who are credited with post-ups are better than Melo. Portland only has 4 players who post-up according to the numbers: Hassan, Skal, Merlo, and Hood
* Melo scores 0.92 points/post-up. As a team, the Blazers score 1.24 points/shot. So then, every time Melo posts-up, he will score on average 0.32 less points than Portland's generic FGA.
* taking that further, Melo averages 4.1 post-ups a game, meaning Portland is losing 1.3 points a game from Melo's postups compared to their average. The perspective on that is Portland's margin of victory right now is -1.9. Replace Melo's post-ups with a generic play and Portland scores 1.3 more points a game
* more perspective: here are some of the players better than Melo at post-up: Bojan Bogdanovic (1.11 ppp), Rhonda Hollis-Jefferson (1.00), Demar Defrozan (1.05), Devin Booker (0.95), Danilo Gallanari (1.07), Miles Bridges (1.21), Larry Nance Jr. (1.16), Marvin Williams (1.11), John Collins (1.09, Luka Doncic (1.08), Jabari Parker (1.06), Harrison Barnes (1.02), Mo Harkless (1.00)
I think the age of the three-point shot has reduced the impact of post-up offense. Only 37 players average 1.00 points or more on post-ups and 13 of those post-up less than 5% of their possessions. I'm not going to calculate what each team averages on points/shot but Portland averages 1.24 and they are only 17th in TS% so I'd imagine they are about average in points/shot
A really good post-up big man may collapse a defense enough to open up perimeter shooting opportunities, providing that big is good at moving the ball inside>outside. Many aren't
Maybe the best impact of a post-up would be drawing fouls, but Melo's FT rate is only .187, about half that of Dame and less that Bazemore or Swanigan
Obviously, all those numbers wouldn't flow smoothly in an either/or manner, but if Portland brings back Melo because of post-up offense they are doing something stupid