With a World Cup looming and no guarantee of a place with the Blues, Robinho has been frantically searching for a solution.
However, City are adamant their British record signing will not be allowed to leave unless all the player's wages are taken care of, something that has ruled Benfica out of the running.
"The World Cup in June is a big problem for him," said Mancini. "He wants to play for the national team. I understand that but I must decide what is best for the team.
"I have five or six strikers to choose from, which makes it difficult for him and me."