Real Madrid midfielder Kaka wants to leave the Bernabeu before the transfer window closes, according to BBC Sport.
The 31-year-old playmaker faces stiff competition for a starting berth, with the likes of Mesut Ozil, Isco and Luka Modric all vying for a first-team role.
With such talent in their midfield, Kaka fears he will not get much game time under new boss Carlo Ancelotti, whom he played under during his time at AC Milan.
And having asked to leave the La Liga giants, Manchester United could launch a renewed attempt to land the 2007 World Player of the Year.
David Moyes' side were heavily linked with Kaka just a few weeks ago, with reports suggesting the Old Trafford outfit were lining up a double bid for Kaka and Madrid teammate, Mesut Ozil.
However, with the latter confirming his intentions to stay at the Bernabeu and fight for a first-team role, Manchester United must focus their attention on Kaka - if they decide to renew their interest.
In an interview with BBC Sport, Kaka said: "The club knows I want to leave and I would like them to help me find a solution for my exit.
"Things are difficult for me here, there is less room in the squad all the time.
"I am ready every day to train and work but that does not mean that I am happy."
Manchester United have been given a boost in their pursuit of Kaka, after he ruled out a return to his native Brazil.
"I cannot go to Brazil because the market is closed, the exit would be within Europe," he said.
"I don't want to talk about clubs because I have none at this stage."
Kaka started his career at Sao Paulo before moving to Milan, where he won the Ballon d'Or and Fifa World Player of the Year award.