The 25-year-old has struggled to recreate the performances of his four-year Juventus stay since a then-world record £89m move from Serie A back to United in the summer of 2016.
United can still receive offers for players after Thursday, but will not be able to pursue targets to replace Pogba.
Pogba has yet to return to pre-season after his World Cup exploits in Russian Federation, despite the fact United kick off their Premier League season on Friday.
However, Pogba continues to be linked with a move away from the 20-time English champions after two mixed seasons and reports of fallouts with manager Jose Mourinho.
United said last night that Pogba was not for sale amid claims that Barcelona and Juventus want to sign the World Cup victor before the European transfer window shuts at the end of the month.
The United manager claimed that the summer tournament - which Pogba's France won in Russian Federation - is the "perfect" environment for him because he "can only think about football" as opposed to other outside influences.
Rick Gates admitted he committed crimes for Manafort while working for him
Similar to prior witnesses, Ms Laporta testified Mr Gates and Mr Manafort were in lockstep but that Mr Manafort was in charge. Manafort has pleaded not guilty to 18 counts of bank and tax fraud and failing to disclose foreign bank accounts.
'I don't think it's about us getting the best out of him, it's about him giving the best he has to give, ' said Mourinho last month.
'The players are in a closed camp, isolated from the external world, from commercial compromises, and every possible influence'.
Pogba was inconsistent last season and was even dropped by the United boss for a spell in the second half of the season.
The fact Raiola, who was in the north-west yesterday, is trying so hard will only increase the belief the players wants out of United after just two years.
In theory, Barcelona would have until the end of the month to sign Pogba before the transfer window closes in Spain.
But, Gianluca Di Marzio.com claim Barcelona have made the first move to sign Pogba by offering a player the club knows United would like.
Mina, Leicester's Harry Maguire and Tottenham's Toby Alderweireld have been the alternative targets as Old Trafford executive vice-chairman Ed Woodward looks to deliver the new centre-back that Mourinho wants.