You called him one of the worst, don't change your story now. And what is your criteria for placing him 20th? Just the eye test? Because I've already proved that he's better than 20 just on stats.
Looking around the league's projected starters, I'd say he's better than Missi (Pelicans), Mark Williams (Hornets), Gafford (Mavs)but I'd take Dallas' overall center situation above ours, whoever Golden State is running out there, Mitchell Robinson (Knicks), Carter (Magic), Poeltl (Raptors).
That is pretty much the list of starters I think he's better than. I could be talked into taking him over Claxton or Zubac.
Jalen Duren and Zack Edey are young and unproven but I fully expect both to have better seasons than Nurk.
So... yeah, somewhere in the 20s, firmly, that is pretty fair, IMO.