well you gotta think ideally they would want OP14 to last for a full 26 episode season and you'd think they'd do half Sabo and half training for the timeskip. The Sabo flashback in total after counting the next 2 weeks will be 12 episodes. Then there was the One Piece x Toriko crossover right before so there's half of your season right there.
13 episodes of wrapping things up with Rayleigh training Luffy and each of the training the Straw Hats will do before the timeskip bank on it
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