MacDonald, who has been in charge of the reserves, will oversee the first team for Villa's opening game of the new Premier League season against West Ham on Saturday before a trip to Newcastle on Sunday 22 August.
In-between, they begin their European campaign with a Europa League qualifying play-off first leg against Rapid Vienna on Thursday 19 August.
United States manager Bob Bradley, Ajax boss Martin Jol and Germany legend Jurgen Klinsmann are among those being linked with the job.
Ex-England coach Sven-Goran Eriksson and former Villa star Gareth Southgate are both also believed to be interested.
Earlier, Lerner's right-hand man General Charles C Krulak said he believed O'Neill quit as manager because of the financial limits he was expected to work under and because he thought he was bigger than the club.
"No one person is bigger than our club. Not me, not Randy, not chief executive Paul Faulkner, not Martin," he told the
"What's interesting is that apparently only three of those understand that.
"There is no question he did a good deal for Villa and I've said over and over that he did a fine job.
"At the same time, I can promise everyone that he knew and understood the long-range plans for the club and bought into them.
"Martin was absolutely supported by the owner. All one needs to do is look at the money spent.
"The reality is the wage-to-revenue issue was not addressed and apparently he was unwilling to help address it.
"He knew full well about the need to bring wages in line with revenue - the same as every Premiership club."
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