The 31-year-old has hinted over recent weeks that he is keen to leave the Premier League champions, with his agent having also hit out at the way that his client has been treated by the club.
However, former Manchester United defender Parker has sided with City, who he has described as too big to bow down to one player.
"The big question mark for them though has to be Yaya Toure. At the end of the day, they don't need a sour apple in the barrel. City have reached a level where they have to be bigger than any one individual and it is one player who is causing problems. He has to go," Parker wrote in his Eurosport column.
"His actions since the season has finished are the actions of a man who wants to leave. What he is doing now is the same as what he did at Barcelona, it is just the excuses that are different. He always seems to be chasing money so what City need to do is turn around and say to him - 'fine, you can go.'"
Toure has been linked with a number of clubs, including his former team Barcelona, as well as Real Madrid.