Having already seen an approach for Wolfsburg's Diego fall through, the director does not believe the Argentine or any other playmaker will sign for the Mengao
The Rio giants are keen to add a high-profile playmaker to their squad following the acrimonious departure of Ronaldinho to Atletico Mineiro, and had been strongly linked with the 34-year-old Argentine.
Riquelme emerged as a serious target for both the Fla and Cruzeiro, following his revelation at the Copa Libertadores final that he would not continue playing for Boca.
Speaking on Wednesday, however, Zinho admitted that Flamengo fans were unlikely to see either the veteran No.10 or anyone else join before the international window slams shut.
"We cannot create hope for the fans. I go out in the street, take two steps and a fan stops me to ask, 'Who is coming?' Two names come out of my mouth, Diego and Juan [Riquelme], deals that were not completed. I think it will be hard to sign a player before Friday, it is not easy," the director told Globoesporte.
"We are working hard, within our own financial limitations."
Elaborating on the rumours that linked Roman to Rio, the 1994 World Cup winner denied that there had ever been contact between player and club.
"I never went for Riquelme. When he announced that he would leave Boca after the Corinthians game, and we were looking for a No.10, that pressure began.
"As far as I know, he still hasn't rescinded his contract with Boca, he just said he would not play there anymore. Right now he is not free."
Riquelme missed out on a fourth Libertadores title following the defeat at the hands of Corinthians, who ran out 3-1 winners over two legs.