Rule 307.5 · Sorceries
If a spell, ability, or effect states that a player can do something only “any time they could cast a sorcery” or “only as a sorcery,” it means only that the player must have priority, it must be during the main phase of their turn, and the stack must be empty. The player doesn’t need to have a sorcery card they could cast. Effects that would preclude that player from casting a sorcery spell don’t affect the player’s capability to perform that action (unless the action is actually casting a sorcery spell).
Subrules
Similarly, if an effect checks to see if a spell was cast “any time a sorcery couldn’t have been cast,” it’s checking only whether the spell’s controller cast it without having priority, during a phase other than their main phase, or while another object was on the stack.