Hold on — this article is actually about Middlesbrough boss Michael Carrick, not Manchester United's coaching staff, despite the confusing headline referencing Rashford and Mainoo.
According to BBC News, Carrick has used the buildup to his first full season in charge to stress that his squad needs further reinforcements before the campaign gets underway. The report notes he spoke about feeling fortunate to be in his current position, while also touching on the futures of Marcus Rashford and Kobbie Mainoo — though specific details of what he said about the pair aren't included in the source material.
Given the limited information provided, it's unclear exactly what business Carrick wants done or what he said regarding Rashford and Mainoo's situations. GoalPoles will provide fuller coverage once more concrete details from the interview emerge.