First team only use him as a winger. We play him as a 10.

I would not automatically change his U18 role completely. If the first team see him as a winger, he needs enough exposure there to understand the senior expectations and build relationships in that position. But playing as a 10 for the U18s may still develop qualities that make him a better winger — receiving between lines, combinations, scanning and creating. The key is communication between the two staffs. What exactly does the senior coach need him to improve as a winger? Can some of that be addressed inside the U18 role, or does he need a block of games wide? I often prefer adding the senior role rather than removing the youth one immediately. At U18, versatility can help a pathway if the player understands the different demands. The goal is not identical team sheets across age groups. It is preparing the player for the opportunity that is realistically available while continuing to develop their wider game.