Jose Mourinho has suggested Manchester United should not be worried about selling Wayne Rooney to Chelsea and insists there have been no discussions regarding the future of Juan Mata.Mourinho also cited his own example of selling William Gallas to Arsenal during his first spell as Chelsea manager as a reason why United should not be afraid of letting Rooney move to west London. He continued: "Players are sometimes unhappy because they want new contracts and at other times they are unhappy because they want to leave and that is a different situation. "Other times it's because they really want to go. I was so sad about William Gallas. He was fundamental for us when we won titles. "He said he wants, he wants, he wants and we couldn't stop him, so we decided not to stop him. "As you know, in this club it wasn't an economical problem, it was just the player wanted to go. Ricardo Carvalho and John Terry were playing central defence all the time and he wanted to be first choice. "He was playing many matches in a position that wasn't his best position, he was playing left-back and sometimes Wayne Bridge was playing, so he wasn't happy. So we thought it was a fair situation to sell him in the end. "I had no trouble selling him to a rival. It happens all the time in Europe."