When a player gets into a fight in hockey, he gets thrown in a “box” for some time. Mike is probably referring to just keeping everything that he gets for being in OF (shoes, clothes, money, etc.) in some sort of separate part of his life which is completely different from his “real” life.
Alternatively, they all get free supreme shit and vans that come in boxes. the endorsements they get are shipped in boxes from which they are never removed because they get so much of it.
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