Adjusted +/- is not totally useless, but of course it can be deceiving and doesn't tell even half the story.
Take Matt Bonner. His +/- doesn't mean he's better then Duncan, etc. It does tell me that he is a useful player that helps his team when you dig deeper.
What Fields +/- tells me is that he is not hurting this team. Too many people say he is useless and is killing the team. They make it sound like we are playing 4 on 5 on both ends of the court. Or that Fields kills our spacing and the offense can't operate. What the +/- tells me is that the team is successful with Fields on the court. When you dig deeper you can see why. Fields is:
#9 among SGs in Assist to TO ratio
#6 among SGs in steals
#4 among SGs in rebounds
#3 among SGs in fg% (if he qualified...doesn't qualify because he plays within himself)
Fields is a very underrated passer/ball handler. He consistently makes some really nice passes every game. He runs the pick n roll very well. Overall he makes good decisions thus his high assist/TO ratio.
His high fg % is a result of getting so many dunks/layups. Its not an accident that he gets so many dunks and easy baskets. Its a skill to be able to cut or get out on the break or be in position to catch an alley oop. Its a skill that helps spacing. Its not an easy skill to have else everyone in the league would be shooting 50%.
His high steal and rebound numbers is a result of hustle and length. He is able to tip a lot of balls and create turnovers. He's in the right spot at the right time because he has a good court awareness.
In general, we do have good spacing with Fields on the floor which is why the team is successful. Its because you do not need to stand outside the 3 point line in order to properly space the floor. ts a false notion that you need 4 guys around the 3 point line. The triangle offense is a great example of how its possible to isolate and provide great spacing with cutters and players on the weak side. Nice, timely passing is also a must in order to space the floor. Fields swings the ball very quickly and to the right spot. That along with Fields ability to play off the ball and cut helps our ball movement which has been a key to our offense.
Of course Fields has his weakness's. His shot has been terrible. I don't think anyone is saying he should be playing 30/35 min a game. But he is fine in the roll he is in now. No doubt we could upgrade, but right now he is our best option to start.
C: Demarcus Cousins | Garnett | Amundson | Willy Hernangomez
PF: Taj Gibson | Marvin Williams | Montrezz Harrell
SF: Matt Barnes | Kyle Singler | Sam Dekker
SG: Klay Thompson | Barbosa | Vince Carter
PG: Mike Conley | JJ Barea