Just a minor clarification on the rule. A player with junior eligibility can be returned to his junior club at any point, even after he has played in 10 NHL games. It'll never happen though because was that player hits 10 games, it counts as a year of service on his contract, essentially starting the clock ticking towards his free agency status (7 years of NHL/AHL hockey). I guess that could happen if a player really went into the tank and the team needed a roster spot badly.