Eintracht Frankfurt would reportedly be prepared to sell Andre Silva this summer if they received an offer in the region of €40m (£34.6m).
The 25-year-old has been in impressive form at club level during the 2020-21 campaign, scoring 24 times and registering nine assists in 28 appearances in all competitions.
According to Bild, there is no release clause in the Portugal international's contract, but Frankfurt would be open to offers in the region of €40m (£34.6m).
Silva is thought to be seen as an alternative to Borussia Dortmund's Erling Braut Haaland, who is likely to cost upwards of £100m if he moves on during this summer's transfer window.
Barca and Man United are both said to be in the market for a new striker ahead of next season, with Luis Suarez leaving Camp Nou last summer and Edinson Cavani potentially exiting Old Trafford later this year.