Rafinha, Thiago's 20-year-old younger brother, is also on the books at Barcelona and has been linked with a loan move to Everton.
But the report claims David Moyes may attempt to sign him up if it aids United's pursuit of his brother, the £15m-rated Thiago Alcantara.
The Spain under-21 captain starred at the recent European under-21 Championships in Israel, and has been linked with a move to United after his release clause dropped to €18m due to a lack of playing time at the Nou Camp.
Rafinha is being sent out on loan next season by Barcelona as they look to give the youngster first-team experience.
Chelsea and Arsenal are keen, but Moyes is believed to be willing to take the Brazil under-20 international if it helps land his brother.
The report claims the Alcantara family would relocate to the north west if Rafinha moves to Everton or United, with his brother likely to follow.
And Thiago's father, ex-Brazil international Mazinho, recently spoke out in favour of his older son joining United ahead of the likes of Manchester City, Bayern Munich and Chelsea.
Thiago has been urged to join the Old Trafford club by Spain teammate David De Gea, and he's believed to be considering a switch after becoming frustrated in his search for first-team football at the Nou Camp.