Phelan had words of encouragement for new signings Kagawa and Powell as they continue to integrate with the rest of the squad following their summer arrival.
"We've introduced Shinji into the team now playing in a certain role and we need the other players around him to understand what he can bring to this team," he told MUTV. "The same goes for Nick Powell. He's made a huge jump from Crewe to Manchester United but he needs to learn what it takes to be a regular first-team player because he is a young boy.
"We've seen instances in games, not just games in the main group but also the second group, that he's more than capable of adapting."