Question though: if you plan on Williams getting: 28 minutes a game, 10FGA's, 52% shooting and 39% 3pt shooting for 15 pts and 6 boards.
then why on earth is he only playing 28 minutes per game? Gallinari played 34 and 30 min per game between 2 NBA playoff teams. If Williams is already better in almost every facet of the game, shouldn't he be playing at least that much? Which would then increase those # totals? (Which is what led me to presume you think he's going to play at an all-star level)
3 Reasons:
1) Defense, both his and theirs. He'll have a really tough time defending NBA 3's on a regular basis, especially if he's fatigued. Other teams will also gameplan around him more intensely if he starts and plays 33 minutes a night, which runs the risk greater that he'll have rookie mistakes be much more costly.
2) Post players in the NBA are more physically demanding, the game is faster, the players set harder picks, they're harder to intimidate, you get less plays 'off' where you aren't challenged as hard. Rising to meet that challenge night in, night out is a tough thing for even the best rookie to manage. It takes a truly special kind of player as a rookie to play effective 2-way basketball night in night out and play it at a high level as a starter for 30+ minutes. Maybe Derrick Williams is that guy, but I don't think I need him to be, and I'd rather bring him along slowly.
3) Rookies hit walls. That's why its called a 'Rookie Wall'. Somewhere in the 2nd 3rd of the season to the 3rd 4th, the rookie runs outta juice.
That can be sped along and/or made more painful by playing them too much, and asking too much of them mentally and physically. I think with my plan Derrick Williams gets the minutes he needs, without getting the burden he can't handle.