Is Snowhorn Rider legal in Standard, Modern, and Commander?

Snowhorn Rider is legal in: Modern, Pioneer, Legacy, Vintage, Commander, Pauper, Historic.

What type of card is Snowhorn Rider?

Snowhorn Rider is a Creature — Human Warrior. Its oracle text reads: "Trample Morph {2}{G}{U}{R} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.) *Sure-footed, strong-willed, and ill-tempered—and so is the ram.* Power/Toughness: 5/5"