Is Fleshless Gladiator legal in Standard, Modern, and Commander?

Fleshless Gladiator is legal in: Modern, Pioneer, Legacy, Vintage, Commander, Pauper, Historic.

Fleshless Gladiator

Q: What type of card is Fleshless Gladiator?

Fleshless Gladiator is a Creature — Phyrexian Skeleton. Its oracle text reads: "Corrupted — {2}{B}: Return this card from your graveyard to the battlefield tapped. You lose 1 life. Activate only if an opponent has three or more poison counters."

Creature — Phyrexian Skeleton

Corrupted — : Return this card from your graveyard to the battlefield tapped. You lose 1 life. Activate only if an opponent has three or more poison counters.