How will Michael Owen be viewed in future if he completes his unexpected free transfer from Newcastle United to Manchester United? Will he prove to be one of Sir Alex Ferguson’s most astute signings – or will he join the list of Old Trafford failures?

Ferguson's five best signings

Denis Irwin, 1990
The full back was 24 and playing in the second tier with Oldham Athletic when Ferguson signed him for £625,000. But he went on to make more than 500 appearances for United, winning seven league titles, and was equally effective at right back or left back.

Eric Cantona, 1992
The Frenchman inspired United to end their 25-season title drought, collecting four league winner’s medals in his five years at the club. His diligent training also set a fine example that was followed by many young players at the club.

Roy Keane, 1993
Keane, then of Nottingham Forest, had already told Kenny Dalglish he would sign for Blackburn Rovers but Ferguson stepped in and coaxed the Irishman to Old Trafford, where he enjoyed a dozen great years.

Teddy Sheringham, 1997
Sheringham was 31 when Ferguson took him to Old Trafford and he proved an excellent replacement for Eric Cantona. Both lacked speed but their vision and passing ability just behind the main striker made them pivotal figures.

Cristiano Ronaldo, 2003
Ferguson’s trust in youth was emphasised when he signed the 18-year-old from Sporting Lisbon. The Portuguese became the world’s best player under the Scot’s tutelage.

Five worst signings

Ralph Milne, 1988
The former Dundee United winger was an unqualified failure. “I don’t pretend that it was the best piece of business I ever did,” said Ferguson. “Old Trafford was simply too much for him and he faded into the shadows.”

Massimo Taibi, 1999
United paid Venezia £4.5million as they sought a replacement for Peter Schmeichel but the Italian lasted only four months. His defining moment was letting in a gentle shot by Matt Le Tissier for Southampton.

Juan Sebastian Veron, 2001
The Argentine midfield player showed the odd flash of genius, especially in Europe, but in general he was a huge disappointment for a player who had cost United £28.1million from Lazio.

Eric Djemba-Djemba, 2003
So bad they named him twice, as the saying went. An aggressive central midfield player who was viewed as a potential successor to Roy Keane, he played a full part in United’s post-2003 decline.

Kleberson, 2003
“He [Sir Alex Ferguson] never showed any confidence in me after the first few months,” the Brazil midfield player complained after leaving in 2005. That showed the manager had come to his senses after his poor decision to sign the player.