Jose Mourinho's arrival at Old Trafford has coincided with a whole host of big-name signings, as the Portuguese looks to mould the side he inherited from Louis van Gaal into one that resembles his own.
With so many high-profile arrivals, there will likely be plenty of exits this summer, with Mourinho renowned for his preference to work with a small squad.
One player who has been linked with a move away from the club is Marouane Fellaini, with former manager David Moyes admitting his desire to bring the 28-year-old Belgian to Sunderland (The Guardian).
Slaven Bilic has been gradually adding to his options throughout the summer, but one area where they still appear to be a touch one-dimensional is midfield.
Manchester United's Marouane Fellaini and Wayne Rooney look dejected
They have fantastic footballers such as Mark Noble and Manuel Lanzini, but lack a real presence, especially when Cheikhou Kouyaté is absent.
While Kouyate has been excellent for the club, he is more a box-to-box type midfielder, so Fellaini would bring something entirely different to the Hammers line-up, and provide Bilic with the option to play with more tactical variety.
If a move came to fruition, the East London club would possess two players with arguably the best aerial ability in the league in Andy Carroll and Fellaini. The threat posed from corners and set-pieces would be a significant one and give the Hammers an increased goal threat.
Manchester United's Marouane Fellaini
Fellaini is also excellent at helping out in the defensive department and would assist the West Ham back-line in defending set-pieces.
The former Everton star's ability to play in both the holding-midfield role and a more advanced position would provide the Hammers with much needed versatility in the middle of the park - something that could prove vital with the amount of games they will face this season.
Fellaini is under contract at Old Trafford until 2018, so a fairly substantial fee would still be required to snare the Belgian, but West Ham should consider a move nevertheless.
Manchester United's Marouane Fellaini celebrates