Van Nistelrooy left Old Trafford under a cloud in the summer of 2006 after falling out spectacularly with Ferguson over tactics and team selection issues at United.
Good call: Ruud Van Nistelrooy has made up with Sir Alex Ferguson
The former Dutch international - now at Hamburg in Germany - is not the only player to leave United in unhappy circumstances. David Beckham, Jaap Stam and Dwight Yorke - for example - were all ushered out of the door after relations with Ferguson broke down.
But Van Nistelrooy is perhaps the first player to make an attempt to patch things up with a manager for whom he scored more than 100 goals.
Van Nistelrooy said: 'I had been thinking about it for a while and talking it through with my wife.
'She suggested I sent Ferguson a text message to see if he was willing to talk so I sent him a message asking if I could call and he replied to say: 'OK call me at this date and time'.
'I rang him and he answered and said: "OK, go ahead."
'I said I wanted to apologise for what had happened and he said "OK, I appreciate that, when we meet again it will be OK."
Van Nistelrooy was a huge success at United. winning the Premier League, FA Cup and League Cup after joining from PSV Eindhoven in 2001.
But his relationship with Ferguson deteriorated at the end as Ferguson became disenchanted with his star striker's attitude. Van Nistelrooy, for example, famously clashed with Cristiano Ronaldon in training and was then left on the substitutes' bench as United beat Wigan in the 2006 League Cup Final.
Van Nistelrooy added: 'Two or three times every year I would think to myself what a shame it was that it ended like it did with Ferguson. I wanted to do something about it.
'I was really pleased with the phone call.
'I said to him: "Those five years at Man United were fantastic, and working with you, and it's unfortunate what happened."
'If I encounter Ferguson again - and I really hope that will happen - I will embrace him and then it will all be finished.'
Sign me up, Fergie! United veteran Giggs wants new deal at Old Trafford Martin Keown: Ferdinand and Vidic have made United an impregnable force
Explore more:People: Dwight Yorke, Alex Ferguson, David Beckham Places: Germany