Rules glossary
↑ Parent rule: 509.4 If a creature is put onto the battlefield blocking, its cont…
509.4a If the effect that puts a creature onto the battlefield blocking specifies it’s blocking a certain creature and that creature is no longer attacking, the creature is put onto the battlefield but is never considered a blocking creature. The same is true if the controller of the creature that’s put onto the battlefield blocking isn’t a defending player for the specified attacking creature.
No sub-rules.