Even though it becomes clear that Gordy and Junior are "a tribe of two" because they are both outsiders, the reality is that Gordy will never be Rowdy. Junior knows this. It becomes clear to Junior when Gordy responds after being thanked for standing up for Junior that Gordy "didn't do it for (Junior)...(he) did it for science." This sums up much about their friendship and while it does advance in the novel, it is nowhere near the emotional intensity of Junior and Rowdy.
Gordy lacks the depth of Rowdy. Rowdy feels empathy for Junior because of the torment and pain in his own life. Whenever Rowdy needs assistance in terms of a place to stay, emotional or physical shelter, Junior is there. There is a loyalty that is heartfelt within Rowdy towards Junior. This emotional bond to this extent is lacking between Junior and Gordy. Their association is valid. Yet, it is constructed because of the situation in which both of them are isolated from all else. In the relationship between Junior and Rowdy, there is a sincere depth to their relationship. Junior needs Rowdy as much as Rowdy needs him. The level of anger that Rowdy feels towards Junior is out of betrayal and hurt. It becomes clear that Gordy does not view Junior in this same realm. This is why Gordy could not replace Rowdy. The ending of the novel demonstrates this. While both of them live in different worlds, Junior and Rowdy play one on one basketball, without keeping score, knowing that they are bound together in so many different ways. Gordy does not possess this with Junior and, to this extent, Gordy will not be able to replace Rowdy.