That's one model for it, for sure. But, all we have is contextual evidence to indicate what Walsh's role at the club vis-à-vis Koeman is. It seems, from what I've seen, that Walsh is some sort of chief scout and recruiter and that he works in tandem with Koeman to make decisions. It seems, structurally, more democratic/egalitarian and less hierarchical than the director of football/head coach system.