Gerard Houllier has admitted that he is yet to put pen to paper on a three-year deal with Aston Villa.
The Frenchman was brought in as a replacement for Martin O'Neill, who left the club only five days before the beginning of the season following a disagreement with owner Randy Lerner.
The former Olympique Lyonnais boss agreed to take charge at the Birmingham-based club about two weeks ago, and will make his managerial debut with the club on Wednesday in a League Cup tie against Blackburn Rovers.
Despite having not yet signed a deal with the club, the 63-year-old insists that it is only a formality that will soon be completed.
When quizzed as to whether he had signed the contract, Houllier told reporters: "No, not yet but it is okay.
"The word is more important than the rest. You mean physically? No, but don't be worried.
"This is not important - I think at Liverpool, I didn't sign until November or December."
In the meantime, MacDonald - who was caretaker manager for seven games - turned down the opportunity to work with the new gaffer and the first-team, as he decided to return to coaching the reserves.
Houllier said: "I understand why he didn't want to be there. Let's be honest, he was a bit disappointed because he was interviewed like the others.
"But I trusted him to be my number two and I trust him to be the reserve coach which, to me, is someone you work with all the time. He is part of my staff."