Manchester United are currently in talks with Bayern Munich over a proposed deal for defender Jerome Boateng.
Sportsmail reported last week that the former City defender had been offered to Man United after his move to PSG collapsed.
Bayern are prepared to accept around £45million for the 29-year-old defender, who will clock 30 next month, but United want to drive the price lower.
Mourinho is keen on bolstering his backline which remains his priority heading into the new campaign. The Portuguese manager is banking on United chief Ed Woodward to wrap up the deal.
Boateng a half-time substitute for Bayern on Sunday night has emerged as a serious alternative to Harry Maguire who is being priced out of a move by Leicester.
Talks are understood to have taken place between United and their German hosts on Sunday night over Boateng. United would want to reduce that fee of £45m to nearer £40m.
The Red Devils will be hoping the deal is wrapped up before the transfer window shuts down on Thursday.