According to the Guardian, the Serbian international will undergo a medical on Sunday (30 July) before sealing a switch to Old Trafford. The 28-year-old has been constantly linked with a move to United, while Juventus were also believed to be interested in securing his services.
The Red Devils managed to beat the Old Lady in signing the Blues star after Matic decided to reunite with Jose Mourinho at United. The Portuguese tactician re-signed him for Chelsea in January 2014 and went on to win the league under the former Real Madrid manager at Stamford Bridge a year later.
Matic played a key role in helping the west London club win the league last season, which was the first silverware with the Blues for Antonio Conte. The two clubs were initially apart over the transfer fee.
United managed to beat in Chelsea in signing Romelu Lukaku from Everton. The Belgium international decided against returning to his former club in order to join the 20-time English champions.
The Premier League winners' owner Roman Abramovich wanted to add "Lukaku tax" in the Matic fee, which saw the price tag rise to £50m ($65.6m). The Guardian report claims it is still not clear as to what the fee will be for the former Benfica man.
Matic was not part of Chelsea's pre-season trip to China and Singapore as Conte left the Serbian and Diego Costa out of the squad. The midfielder was left back at the club in order to seek a new club in the transfer window.
Meanwhile, United are also set to offload Fellaini as the Red Devils midfielder is wanted by Galatasaray. The Turkish club's sporting director Cenk Ergun confirmed his side are close to securing the signing of the Belgium international.
The Guardian claims Galatasaray have reached an agreement in principle with Fellaini. He is set to sign a four-year deal, which will see him earn around €4m (£3.6m) per year. This will make him the highest paid player at the club.