Sporting director Moody resigned from his position on Thursday amid allegations over his conduct at former club Cardiff City.
Moody and former Cardiff manager Malky Mackay are alleged to have exchanged derogatory texts during their time at the Welsh club, withe the FA confirming an investigation is under way.
The pair had looked set to be reunited at Palace amid reports Mackay had been offered the chance to replace departed boss Tony Pulis in the Selhurst Park dugout.
But with that move scrapped, and Moody having now left the club, the task of conducting Palace's transfer business before the window closes on September 1 has fallen to Millen.
"It will go through me really now," said Millen, who has already signalled his intention to try and claim the manager's job on a permanent basis.
"I've asked the scouting department to have a meeting with me today, to discuss the names that we feel we can bring in.
"I'll speak to the chairman then.
"The process has got to be ongoing, and if we do appoint a manager, we can say 'this is what's out there, this is what we think we need', and then hopefully it will be the new manager's final decision."
Pulis had already recruited Martin Kelly, Fraizer Campbell and Brede Hangeland prior to leaving the club last week, but Millen believes that they are still several players short.
"We do need to bring in some players, the days are counting down," he added.
"That's why it's important we do our homework, as we have done all summer, and try to continue with a list of names, that we feel will continue and enhance what we're doing.
"I think it is maybe two or three [new additions]."
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