The Red Devils are keen to add a centre-forward in the summer.
Their main target is Borussia Dortmund star Erling Haaland, but the Norwegian may be out of their reach.
And according to German outlet Frankfurter Rundschau, any club would have to pay Frankfurt roughly £35 million to secure Silva.
The 25-year-old, who has 26 goals in the 2020/2021 season, is joint second in the scoring charts in the Bundesliga.
It is believed Eintracht are likely to sell Silva this summer, and the price is far more affordable than what it would cost to sign Haaland.
Portugal international Silva has recaptured form after failing to establish himself at AC Milan.