The writers actually remembered that Ash had a Primeape! Yup, I'm totally late to the party here. This gives me some hope that if some of Ash's old Pokémon do get called upon for the World Tournament though, that somehow Primeape will be called upon too. It'd be great to see him after so long of thinking that the writers forgot about him, along with Pidgeot and Butterfree. Although, by the looks of it, I don't think we might get to see Pidgeot make an appearance, much less Butterfree. Which makes sense I guess, since it'd be hard to get in touch with them since Ash more or less let them go on their own rather than with someone.
Also, I agree with Kirbychu. I can see the writers bringing in some of Ash's old Pokémon for the World Tournament so they can then later focus on Ash's Unova team for the League. I would like to see some of the lesser used Pokémon come back among Primeape of course. It's always exciting though whenever any of Ash's old Pokémon that we haven't seen in so long come back. Maybe we'll even get another evolution like we got with Cyndaquil in Sinnoh. I'd like that.