Could Michael Carrick be re-trained to become a permanent centre back for a United back three?
This summer has been a summer of change at Manchester United. The club, reeling from a terrible performance on the pitch last term, moved fast to remove David Moyes from his working capacity toward the end of 2013-14.
They have replaced him with Louis van Gaal and the likes of Nemanja Vidic, Rio Ferdinand and Patrice Evra have been moved on - while Ander Herrera and Luke Shaw have arrived at Old Trafford.
But perhaps the biggest change has been the tactical switch at the club - as United go three at the back.
Van Gaal has been implementing the same tactical formation used by The Netherlands at this summer's World Cup - with wing-backs and a back three.
However, with Vidic and Ferdinand departing this summer, the club are short of central defenders - especially now they need three a game.
Phil Jones, Chris Smalling and Jonny Evans are all perfectly capable of playing these roles however youngsters Michael Keane and Tyler Blackett still have plenty of to learn - despite being hotly tipped by Van Gaal himself.
One defender is set to come in - with big fees being mentioned for the likes of Mats Hummels; while it looks as though Barcelona are winning the race for Belgian defender and Arsenal club captain Thomas Vermaelen.
But is there a solution that could solve their defensive problems for free - in the form of Michael Carrick?
Carrick has played at centre back in the past. Sometimes it has worked, sometimes it has been a disaster but Van Gaal is not one to shirk away from a positional retrain and he also likes a ball-playing defender.
Carrick is coming to the end of his midfield days. Fitness and pace are no longer his allies and he will find it difficult to contend with some of the other United players for a place in the first-team.
As part of a defensive trio Carrick will likely find himself under less pressure then when part of a defensive pairing - and slotting alongside Jones and Smalling or Evans he could become a great option at the back.
That being said, Mats Hummels would still be welcome.