The key card is present but its support is thin.
Prioritize useful support such as Raphael, Tough Turtle or Mechanized Ninja Cavalry.
Attack with The Neutrinos and blink Cavalry. Both the returning Cavalry and its new Robot trigger alliance.
Your deck already enables the plan but is losing the early turns.
Take a castable early creature or efficient answer before a second expensive payoff.
The returned creature is already attacking but was not declared as an attacker, so its attack-trigger abilities do not trigger again.
The support is missing
Favor independently useful creatures and interaction if the narrow support does not arrive.