Semi is a second round pick that has stuck around the NBA for 284 games and 24 starts. Athletic but undersized for PF. Not nearly skilled enough to be a wing (but can defend wings fine in switches). I would not call Semi a wasted second round pick nor do a consider Grant a wasted late first round pick. Grant, with his improved 3 pt shooting, is better than Semi, before that, they were remarkably similar.
All that said, I see no role for Semi on our current roster. He is not a center and we don't need another undersized PF since we already have Grant who is better. Certainly hope Semi catches on somewhere. Easy guy to root for. His career earnings to date are about $8.9M. Not bad. I hope he gets a few more years.