Milan defender Jaap Stam claims Manchester United “know they made a mistake” when they sold him in 2001.
The sides meet at Old Trafford in the Champions League game on Wednesday.
“United made a mistake in selling me,” Stam told Uefa’s Champions magazine.
“I was settled at Manchester United, but they wanted to sell me. If a club want to sell you, there is nothing you can do. You can be sold like cattle.”
Sir Alex Ferguson sold Stam to Lazio for £16.5m in August 2001.
“I was settled at Manchester United, I had even just ordered a new kitchen, but they wanted to sell me,” he said.
“In what other industry can a good employee be ushered out the door against their wishes?
“Of course, you can refuse to go, but then the club have the power to put you on the bench. I don’t agree that players control the game.
“There have been opportunities to confront them in the newspapers, but I have turned them down. What’s the point?”
Tonight’s match pits Milan’s vastly experienced backline against two of the brightest propsects in world football in Wayne Rooney and Cristiano Ronaldo.
“We can’t all be Wayne Rooneys – at his age I was training to be an electrician and thought my chance of becoming a professional footballer had gone,” Stam added.
“Starting late can be a good thing. Some kids who start early get bored.
“I had my youth – having fun, drinking beers, blowing up milk cannisters. It sounds strange but it’s a tradition where I grew up in Kampen – and I had done all the things I wanted to do.”