Juventus' Federico Chiesa is Barcelona's preferred target as they look to bring in a winger before the closure of the transfer window.
However, according to Sport, Barcelona are considering Sancho as an alternative option.
The report adds that a loan move for Sancho is unlikely as United would demand that Barcelona would pay the whole of the 24-year-old's salary for the season.
Sancho reportedly earns around £15million a year, which would make such a move hugely unlikely given Barcelona's financial difficulties.
Barcelona are keeping tabs on Man United's Jadon Sancho ahead of a potential loan move
Hansi Flick's side are already currently unable to register new signing Dani Olmo following his arrival from RB Leipzig.
Sancho is back at United after spending the second half of last season on loan at Borussia Dortmund.
Although he previously fell out with United boss Erik ten Hag, Sancho featured for the Red Devils in pre-season after agreeing to start afresh.
Sancho featured in the Community Shield as a substitute but missed a penalty in the shootout defeat to Manchester City.
However, he wasn't involved in United's Premier League opener against Fulham.
Sancho, who was previously linked with a move to Paris Saint-Germain, has made 83 appearances for United and has scored 12 goals.