However, the former Crawley Town manager is confident that his transfer business will be concluded before Saturday's friendly against Middlesbrough.
"We are still one or two short. The chairman has been fantastic and we are working on things," Evans told the club's official website.
"If we can get something sorted before the weekend then we will be ready and it's two weeks early.
"We won't be worried about the transfer window closing because we'll be ready. We are very optimistic, but it is about getting the whole package together."
Rotherham have signed seven new players this summer.