This is useful if you want to see how your roster is shaping up by moving players assigned to an active roster to your bench, another position they are eligible for, etc.
First, move your cursor to the right pane that shows your team's roster. Place your cursor to the right of the player’s name you want to move. A dropdown box will appear next to the player's name. Click on the dropdown box and select the position on your roster you want to move that player to.
This can also be done in the Draft Assistant during a live draft. Also be aware that opponents in the Draft Simulator automatically rearrange their own rosters when it’s necessary.