Alexis Sanchez finally looks set to move away from Arsenal after months of speculation surrounding his future. 

The 29-year-old will be out of contract next summer but is almost certainly going to move to Manchester United by the end of January. 

The transfer will see Old Trafford outcast Henrikh Mkhitaryan move in the other direction, linking up with Arsene Wenger and his team in north London. 

Although United will pay no money for Sanchez, getting Mkhitaryan in return is a good deal for the Gunners, considering they would lose him for nothing at the end of this season. 

But until a few weeks ago, it looked like the Chilean was set to sign for Manchester City. In fact, he came very close to doing so last summer. 

Instead, his huge wage demands and agent fees reportedly put off City and Pep Guardiola to the point where they no longer deem him worth signing. 

Luckily for Sanchez, Jose Mourinho was quick in declaring his interest and before his rival Manchester club had even pulled out of the deal, rumours of a move to United began to circulate. 

And with just 10 days left in the winter transfer window, it looks like the forward has all but completed his move from London to the red half of Manchester. 

Ahead of the official announcement, Mourinho has revealed exactly why he wants to sign Sanchez and his reasoning is quite interesting. 

"In this moment there is no competition for places," he said, per the Mirror. 

The Portuguese boss believes that despite his array of attacking personal, he still needs another player, to create a bit of healthy competition. 

"In this moment we have four attacking players for three positions, three are starting, one is on the bench, Zlatan for the whole season was not available.

"We look to central defenders, played Jones and Smalling, Rojo on the bench, Victor [Lindelof] in the stands, [Eric] Bailly is injured, look to midfield, Fellaini, Herrera and McTominay on the bench, Carrick in the stands. 

"And we look to the attacking areas and we need that extra competitive internal competition but more solutions for us, so let's see." 

Of course, if United are to challenge City at the top of the Premier League, they're going to need a big squad. 

But with all their attacking talent already, it's likely that two younger players, Jesse Lingard and Marcus Rashford, will spend even more time on the bench if Sanchez arrives. 

Lingard, in particular, has had a very good season so far, so he'll be disappointed if Sanchez forces him out. 

But if United do go on to challenge for the league and even the Champions League over the next few months, Mourinho's decision to bring in another forward will be seen as a good one.