RCM: Ander Herrera (£32 million from Athletic Bilbao)
The Spanish midfielder signed by Louis van Gaal in 2014 for £32 million would round off what would easily be one of the most energetic midfield trios in the Premier League.
Herrera, like his midfield partners, might not have a huge bag of tricks with him, but he is one of the most passionate United players on the pitch and his enthusiasm is almost infectious. Even more surprising considering he's not even a "local lad".
Last season under Mourinho was his best one yet. He was a regular starter in midfield, operating in a box-to-box role and contributing equally in attack and defence. But Matic's signing this season has reduced his importance to the team.
He still brings qualities to the side that few other players can. With Kante being the perfect midfield anchor, Herrera would have the freedom to push forward with Pogba and participate more in the final third, something that he hasn't been able to do for a while now.