What did Gene now define as his new purose in life?

From the text:

So to Phineas I said, “I’m too busy for sports,” and he went into his incoherent groans and jumbles of words, and I thought the issue was settled until at the end he said, “Listen, pal, if I can’t play sports, you’re going to play them for me,” and I lost part of myself to him then, and a soaring sense of freedom revealed that this must have been my purpose from the first: to become a part of Phineas.