Crooks is presented as an outsider. He is old, crippled, and black, so he does not think anyone needs him anymore and he is terribly lonely.
When we first meet Crooks, we see an example of him trying to be helpful but being gently rebuffed. Crooks is described as “a lean negro head, lined with pain, the eyes patient” (ch 3). He tells Slim he has warmed up tar for the mule, and offers to put it on. Slim tells him it’s all right, he will do it himself. Then Crooks tells him Lennie is playing with the puppies, and Slim tells him it doesn’t matter. Crooks is trying to be helpful, but Slim does not need him.
As the stable buck, Crooks is “more permanent” than the other men. As a Negro, he also gets his own space because no one else wants to room with him. His age, injury, and color all make him outsiders to the other men. He does not get company, and the men won't allow him to share in the games.
"'Cause I'm black. They play cards in there, but I can't play because I'm black. They say I stink. Well, I tell you, you all of you stink to me." (ch 4)
Lennie finds Crook interesting because Lennie is an outsider too. He tells him about the dream of a ranch. Crooks realizes that Geroge and Lennie do not consider him less of a person. While they are around, he feels needed and worthy again.