papereyesT.R.O.L.I. ^ agreed. It's similar to Ferguson whose only really bad "sell" was Yip Yap Stam (maybe Van Nistelrooy too at a push).
Drugs ban followed about 6 months after the sale so ...
Ferguson himself considers selling Stam as his biggest mistake.
http://www.mirrorfootball.co.uk/news/Selling-Jaap-Stam-was-my-biggest-mistake-as-Manchester-United-boss-and-Dwight-Yorke-and-Andrew-Cole-were-best-partnership-in-Europe-says-Sir-Alex-Ferguson-Exclusive-interview-article402091.html