Rulings

• 2017-03-14
  The second ability doesn't stop players from playing land cards from graveyards or libraries since lands aren't cast.
• 2017-03-14
  If a creature card tries to enter the battlefield from a graveyard or library, it stays in its current zone.
• 2017-04-18
  A noncreature card can enter the battlefield from a graveyard or library if another card's effect (such as that of March of the Machines) will make it a creature after it has entered the battlefield.
• 2017-04-18
  If an object has a static ability that could cause it to become a creature or stop being a creature, that ability is considered when applying Grafdigger's Cage. For example, Rusted Relic can enter the battlefield from a graveyard or library only if you control fewer than three artifacts before it enters. Thassa, God of the Sea can enter only if your devotion to blue is less than five before it enters.
• 2017-04-18
  Applying a replacement effect may cause Grafdigger's Cage to stop an object from entering the battlefield. For example, Sculpting Steel can enter the battlefield from a graveyard or library only if it's not entering as a copy of an artifact creature. However, a replacement effect can't be applied to cause Grafdigger's Cage to not apply. Phyrexian Metamorph can't enter the battlefield even if you wish to copy a noncreature artifact.