Mourinho was expected to sign Lindelof in the January transfer window but opted against a deal due to being satisfied with Phil Jones and Marcos Rojo at the back.
Barcelona have sent scouts to watch Man United target Victor Lindelof
But the Portuguese boss remains keen to sign the Sweden international and is likely to move for him in the summer.
Express Sport understands United will have to pay £50million if they want to bring Lindelof to Old Trafford.
Lindelof is one of Jose Mourinho's top transfer targets
Luis Enrique could be tempted into bringing Lindelof to Barcelona
How Manchester United could look with Victor Lindelof
Wed, December 28, 2016
Is this how Manchester United could look with Victor Lindelof in the starting XI?
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Is this how Manchester United could look with Victor Lindelof?
But Portuguese outlet O Jogo claim United now face competition from Barcelona for his signature after they sent scouts to watch Lindelof play during Benfica's 3-0 win over Nacional on the weekend.
Barcelona are trailing Real Madrid in the race for the La Liga title after some unconvincing form and could hijack United's move for Lindelof by going in for him themselves.
Lindelof has impressed for the Portuguese outfit this season, keeping 13 clean sheets in 25 appearances.