I was really hoping he would emerge as a a Thad Young type PF/Swing but he just didn't. And when it became clear that he wasn't going to be able to give us minutes as a PF, there really was no role for him. Parker, based on last season and this preseason, was not going to give us anything that Hernangomez, GWilliams and even Fernando can give us. The Celtics gave him every opportunity.
To me, this makes some roles more clear:
Smart Schroder Pritchard
Brown Richardson Langford
Tatum Nesmith (2-way fill in)
Hernangomez GWilliams Fernando
Al Horford RWilliams Kanter
This is the roster, not the line up or who will play exactly where. We are going to see all kinds of combinations. We have 3 PFs on the team and 3 Centers. Tatum is our best wing/SF, backed up by Nesmith on the roster. Many of these guys can play different positions but to me, this is the roster.
Things could change, Schroeder may start over Smart, GWilliams may play over Hernangomez, and RWilliams may be ahead of Horford. But I think this is where things stand right now.
I don't know what you saw in preseason that makes you put Hernangomez ahead of Grant Williams.
Also, Tatum will be starting at the 4. The starting lineup, when healthy, will be Smart, Brown, Tatum, one of Horford and Robert Williams, and one of Schroder, Langford, and Richardson.
I tried to be very clear that this was the depth chart or roster, not the line up. There is a big difference. Hernangomez is our best PF in my opinion, which isn't saying much. Grant is right there also. Doesn't mean either will start. Tatum is not a PF. Our starting line up may not have a PF. Doesn't make Tatum a PF.
We should have a pick the opening night starting line up contest. It could be about anything, especially with Brown and Horford out with COVID (I am not sure of their status).
Imo, Tatum is a PF in the pace-and-space era. At the very least, he's at his best when playing at PF. Traditional PFs aren't mobile enough to stay in front of him on the perimeter. This is a massive advantage in our favour, especially since he can put the ball on the floor and create his own shot.
If I had to rank everyone at their best position:
PG: Schroder ≥ Smart > Pritchard
SG: Brown >> JRich > Nesmith > Romeo > Matthews >> Begarin
SF: nobody (maybe Hauser?)
PF: Tatum >>> Juancho ≥ GWill >> Hauser
C: Horford ≥ Timelord > Kanter >> Bruno
I don't trust Hauser to stay in front of explosive wings on the perimeter, hence I put him at PF. Obviously, most of our SGs and PFs can provide cover at SF. I guess CBS was right after all. The 5 positions may be a thing of the past. I mean, our roster is full of versatile tweeners. We also got some players who can fulfill different roles at the same time. For instance, Smart is a wing on defense and a ball handler on offense.
I would argue Juancho is our only traditional PF. No big deal though, cause most traditional PFs suck on D in the pace-and-space era. They aren't mobile enough to defend the perimeter. I view Juancho as a big rather than a swing.