Impossible, unless he terminates his contract with Nike and signs a contract with Adidas
Now he doesn’t have to buy it himself to wear Nike, he has to buy it himself to wear Adidas.
And now that he takes money from Nike, he is obliged to wear Nike. If you wear Adidas now, you will lose money. This is a contract. Once you sign it, just like Yang Bailao, you sold yourself. He sold it for a good price.