In "How to Transform," why does the narrator want to go to the gym in Balboa in the first place?

The narrator waits on the sideline for four weeks, always asking team coaches to let him play and always being told no. Then one day that best player in the gym, Dante confronts the narrator, yelling at him to get out of the gym and go home. The narrator is about to do this when suddenly he turns and says "I just want to play" (17). In response, Dante gives up his own spot in the current game. In the few minutes the narrator gets to play, he impresses everyone and once Dante wants his spot back the other coaches all try to get the narrator to play for them.