Cesar was at Loftus Road on Tuesday to discuss terms ahead of the win over Walsall and looks set to pen a deal with the Hoops.
"There's nothing concluded yet," Hughes said. "There are a number of papers that need to go back.
"We're not at a point where we can actually say it's a done deal.
The intention is there obviously if we can but at the moment it's not concluded.
"I said I wanted to have two quality keepers this window if at all possible. Sometimes when opportunities present itself you want to pursue them.
"When you get an opportunity to possibly bring a player of the quality Julio Cesar's quality, with his playing record and his mentality, then I think you have to pursue to its conclusion.
"I think when we started the process we probably never thought there was an opportunity or chance he would be able to come here. If we are able to conclude it, we'll be delighted."