Put it back. I feel naked without my ball.
Grifball was always at the very bottom of the playlist popularity list when they were published so I doubt it will ever be permanent again.
It’s coming back today for a two week rotation 
You can always see what playlists are coming up next by reading the latest Community Update!
- July 2: Halo 3 Classic Throwback enters into ranked for the month - July 2: Grifball rotates in for Rock ‘N’ Rail - July 11: Castle Wars rotates in for Husky Raid - July 11: Warzone Assault goes live for the weekend - July 18: Covenant Slayer rotates in for Grifball - July 25: Mythic Shotty Snipers rotates in for Castle Wars - July 25: Warzone Turbo goes live for the weekend