The Scot has been in caretaker charge of the Midlands side since Martin O'Neill's departure before the start of the season, and has blooded youngsters such as Marc Albrighton, Ciaran Clark and Eric Lichaj into the first team.
MacDonald takes charge of his final game against Bolton on Saturday before the arrival of former Liverpool manager Houllier at Villa Park after six weeks at the helm.
However, despite Houllier admitting that he was interested in a reunion with former Reds star Michael Owen, who is 30, MacDonald was keen to suggest that the young players coming through should not be cast aside for more experienced campaigners.
"Mr Houllier is inheriting a vibrant young team with some experienced professionals," MacDonald said.
"It can be a team that is going places. I want the team to be in good hands and he has a lot to be excited about.
"The young players trusted me because they knew I trusted them.
"That helped mask their inexperience at this level. I don't know whether they will have to earn the new manager's trust all over again. What I know is they are good players and they have to keep proving that every day in training."