Is Aven Liberator legal in Standard, Modern, and Commander?

Aven Liberator is legal in: Legacy, Vintage, Commander, Pauper.

Aven Liberator

Q: What type of card is Aven Liberator?

Aven Liberator is a Creature — Bird Soldier. Its oracle text reads: "Flying Morph {3}{W} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.) When this creature is turned face up, target creature you control gains protection from the color of your choice until end of turn. Power/Toughness: 2/3"