You get the point of the example, not football boots under the contract, but the jerseys are.
Here I will give you a direct example when we are already talking about large sponsorship contracts in sports. 2008, Wimbledon, Novak Djokovic was then under contract with Adidas, but their sneakers were too slippery. Later it came out in Nike, but with the logo covered. Maybe it was all part of the agreed marketing, but he still covered the competitor's logo to avoid being kicked out of the signature campaign, a violation of the active contract.
https://www.cnbc.com/id/25346774