Animal Athlete Loophole/Playing With

Basic Trope: An animal plays a sport, since there isn't any rule forbidding it.
 * Straight: A donkey plays soccer, since there ain't no rule...
 * Exaggerated: The entire team is replaced with animals.
 * Justified: The rulebook states that anything goes unless specifically noted otherwise.
 * Inverted: There ain't no rule saying you can't enter a human in the Kentucky Derby.
 * Subverted: As it turns out, there is a rule against donkeys playing soccer. Or there is no explicit rule against donkeys playing soccer, but the donkey can't play because he does not meet other established age or medical criteria.
 * Double Subverted: As it turns out, there is a rule against donkeys playing soccer... but not mules.
 * Parodied: "Ain't no rule about donkeys playing soccer." "Yes, yes there is. It's right here in the rulebook!" "Shush."
 * Deconstructed:
 * Shortly afterwords, either the other teams start training their own donkeys, or the rules are amended to prevent this sort of abuse.
 * Or the donkey proceeds to demonstrate in detail why no one wants a donkey playing said sport.
 * Alternately, the team becomes a laughingstock for needing to have an animal play for them.
 * Or the human players are forced in the bench.
 * Reconstructed:
 * Shortly afterwords, either the other teams start training their own donkeys, or the rules are amended to prevent this sort of abuse...and they find "no mules" in the rulebook.
 * Shortly afterwords, the donkey helps the team win.
 * That is, the human players from the other team are forced in the bench. Everyone on the donkey's team is still in play.
 * Averted: Despite the movie heavily featuring a specific animal that does tricks, animals and the sport in question are never mentioned in the same sentence.
 * Enforced: "We want to make a movie about a meerkat playing rugby, so we'll just pretend the rules say nothing about the species of the players."
 * Lampshaded: "Don't you think they'd've been smart enough to close the animal loophole after Air Bud?"
 * Invoked: The sports league deliberately leaves this kind of loophole in its rules in order to encourage its coaches to think outside the box.
 * Defied: The sports league does have rules about the species of the players, just to prevent this kind of situation.
 * Discussed: "I remember last year, when one football team had a bison. That was a crazy season...."
 * Conversed: "What is it with movies about animals playing sports? There should be a rule!"
 * Played For Laughs: PETA develops a sports-agency wing to ensure animal athletes get paid top-dollar.
 * Played For Drama: The player who gets benched in favor of an animal enters a deep, suicidal depression.

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