Sir Alex Ferguson has revealed that Carlos Tevez wasn't signed by Manchester United on a permanent deal because he said he was going to quit football in four years' time. GettyImagesCarlos Tevez waved goodbye to Man Utd • Ferguson: No more signings for us• Chicago Fire 1-3 Man Utd• Rooney eyes Reds challenge• Park set for new deal• Fergie targets Barca rematch Tevez was at Old Trafford for two years on loan, but United chose not to take up the option to keep him and he joined rivals Manchester City. Since then, the Argentine has gone on to become one of the best players in the Premier League, leading many to question Ferguson's wisdom over the decision to let him go. However, the canny Scot has revealed