He absolutely gave it his best shot on post defense at the end of the season. He stuck his face in there and pushed and got after it. He is no dummy. He knew he was dropped from the rotation midseason, because Rose was looking for someone besides Kaufusi to compete inside.
The problem is it isn't his nature to fight and it is so difficult for an athlete to change his spots. I'm not giving up on Neilson at all. I agree he is long and has a lot of potential and skill. That length and skill just needs to be focused in a different area.