Is Gravel Slinger legal in Standard, Modern, and Commander?

Gravel Slinger is legal in: Legacy, Vintage, Commander, Pauper.

What type of card is Gravel Slinger?

Gravel Slinger is a Creature — Human Soldier. Its oracle text reads: "{T}: This creature deals 1 damage to target attacking or blocking creature. Morph {1}{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.) Power/Toughness: 1/3"