Ronaldinho chase drags on
That delay would disappoint manager Alex Ferguson as the club are due to set off on their tour of America on Saturday.
The striker's representative and brother Roberto Assis said Ronaldinho will stay in Brazil until there is good reason for him to believe the talks are nearing a conclusion.
Assis insists that completion of the transfer remains on the horizon rather than being imminent.
"I don't think that the signature will take place this week as Ronaldinho is still in Brazil and has things to do," Assis said.
"We are very optimistic," he added when asked how talks between United and his current club Paris St Germain are advancing.
"I am very happy for my brother and myself. We are waiting for the clubs to reach an agreement before Ronaldinho returns from Brazil.
"Things are progressing well but I prefer to be sure that things between Manchester and PSG are resolved before being completely happy.
"We don't want to wait too long before Ronaldinho comes back."
In addition to Ronaldinho, United are also keen on bringing in his Brazil team-mate Kleberson from Athletico Paranaense.
At a press conference to unveil American goalkeeper Tim Howard as his latest signing, Ferguson said: "We are obviously pursuing the Ronaldinho thing very intensely now, it's getting to that stage.
"It's maybe just about there, we don't know. We are very close."
On Kleberson, the Old Trafford boss said: "We are pursuing an interest."
Ferguson revealed that he expects 24-year-old Howard to challenge Fabien Barthez for the number one spot and perhaps emulate the legendary Peter Schmeichel.
"The important thing is that Tim will be given an opportunity, but a coach can't guarantee anyone his position he has to do that himself.
"His reflexes are very quick and he has a good presence.
"I'm nothing but impressed and his performances in the Confederations Cup were superb.
"There's always competition; in the case of Tim he's got the ability and he's got youth on his side.
"It's a different environment but we said the same thing about Peter Schmeichel and we know what happened there. We wish him a great career at Manchester United. We know he's going to enjoy it, he's come to a really good club.
"It's not been easy. The difficulty is that he was over in the US and the fact he's not a European citizen but we managed to secure the work permit last Friday."
Howard admitted his arrival at United had been a "fantasy".
"Hopefully I have some good tools and I can exploit them," he said. "It's a fantasy really to even think you'll play here but when the interest came about it was humbling and exciting. It's the best club in the world without a doubt."
Meanwhile Ferguson also moved to calm speculation linking Juan Sebastian Veron with a move to Chelsea, saying: "Until there's something concrete there's no point talking about that.
"The player is happy here. The circumstances may change I don't know the offer."




