[jmknpk2]

I'm not aware. Someone else may know a way.

I would create the league.
Then use the "Release all players/clear rosters" function on the League Settings screen, available from the "Available League Actions" drop/down, hovering over "All League Functions".
The released players will be free agents.
Then from the League/Transactions screen Free Agents tab, Available Actions drop down, "Delete all free agents".

You must be commissioner to do this. Check the "Play as commissioner" check box on the Manger Settings/Control and Autoplay screen.

I would be careful to delete those players before I associate the minor league with the major leagues or any other league. Because otherwise the released free agents would be dumped in the same free agent pool as major league free agents you probably don't want to delete.

I believe if you initially create the league with only two teams, only those two teams will be filled with players. Teams added later in the League Settings/ League and Teams screen will be created without players. So you also have the option of doing that and then manually deleting the players from only two teams.