Supporting cast to do what? Try to win now or build for the future?
Does Ben Simmons count as a reserve?
What about a player that starts but plays less than 24 mpg? Is he a starter or a reserve. Think a guy like John Henson.
No matter the answer to the questions above, Greg Monroe is clearly a "reserve" I would want on this team (and he might very well start). I'd also probably go with Zach Randolph as a "reserve"
As for other reserves in contention: Mike Muscala, CJ Miles, Al Jefferson, Stanley Johnson, Derrick Favors, Joe Johnson, Nikola Mirotic, Brandon Jennings, Brandon Knight, Leandro Barbosa, Jeff Green, CJ Watson, Kelly Olynyk, Terry Rozier
As for the starter, Gobert, Adams, Caldwell-Pope, and R. Lopez were all in consideration, but I went with Nicolas Batum, who I would slot in at starting SF.
Looking at everything and going for win now (not the future) I think I would do this, though I'm not overly sold on anyone and could be talked out of any of them.
PG - Thomas, Knight, Jackson
SG - Bradley, Barbosa, Young
SF - Batum, Crowder, Green
PF - Horford, Randolph, Mickey
C - Monroe, Muscala, Zeller