Originally Posted by Ash-kid
Tracey fulfilled his dream when he started to be Oak's assistant. so he actually finished his journey, and because of it Brock returned to travel with Ash and Misty.
Yeah. I never really thought of it that way.
Originally Posted by The 4th KIRA
No, that's why he left, not why he came back.
He came back because:
1) The writers noticed that nobody in the US and beyond cared whether Brock was dark or not.
2) Tracey outgrew his usefulness so they ditched him.
Haha oh! Well that's what I meant. Why he left. I'm glad the US didn't care about Brock being dark.