Well, Air Bud's puppies (in cannon) were almost adult age when puppy napped (for the second time, they were originally puppy napped in World Pup) in Seventh Inning Fetch. Seeing that Buddy appeared for the Angels in the WS at the end of this movie, I think it's a stretch that the puppies would finally be making MLB after Spikes Back. It's known that each puppy was raised to be separately and each uniquely trained for a different sport. I can't imagine that they would all be trying to get to MLB. I could imagine Duran popping up as Josh and Andrea's long lost relative, but it's not something you typically see in an Air Bud joint.