You can activate the regeneration ability even if Goblin Turncoat isn’t at risk of being destroyed. Sometimes you need to sacrifice Goblins. We understand.

Goblin Turncoat can regenerate even if it isn’t in combat, it’s already tapped, or it’s undamaged.

Activating the ability creates a replacement effect that acts like a shield, replacing the next time Goblin Turncoat would be destroyed that turn. This shield works against effects that try to destroy Goblin Turncoat or lethal damage that would be dealt to Goblin Turncoat.