Can you play units to a battlefield?
Yes. When you play a unit you choose a valid location for it, and by default that means your base or a battlefield you control. You can only place it somewhere else if a game effect grants you permission to do so.
Cited rules
- 355.2 For Units, choose a valid Location where that Unit will be placed upon being Played.
- 355.2.a By default, Valid locations include the controller’s Base or a Battlefield the controller controls.
- 355.2.b Some Game Effects may grant players permission to play Units to locations that are not normally Valid. Such locations become Valid for the purposes of Playing the Unit.