Manchester United director of football Jason Wilcox is understood to be particularly keen on the 24-year-old Brazilian.
Transfer journalist Ben Jacobs was the source of the disclosure, telling The United Stand: "While it is very initial and player-led at this stage, Man United are just starting to look at the market in the older and more experienced category of strikers, with one or two exceptions like Igor Thiago — in case Joshua Zirkzee leaves."
Thiago's season at Brentford was exceptional. He scored 22 Premier League goals — second only to Erling Haaland's 27 in the scoring charts — and contributed three more across Cup competitions, finishing with 25 in total for the campaign. Eight of his league goals came from the penalty spot.
He signed a new contract at Brentford in February that keeps him at the club until 2031 with an option for a further year — a deal that gives the west London club maximum leverage in any negotiation. Their asking price is expected to be in the region of £60-70m.
Zirkzee, who scored just two goals in 26 appearances last season starting only five Premier League games, wants to remain and fight for his place under Michael Carrick. However, clubs in Italy, Turkey and Saudi Arabia are circling, and if a suitable offer arrives, Manchester United would be open to facilitating a departure. Only then would a formal approach for Thiago become realistic.
Thiago is currently representing Brazil at the World Cup, where any strong performance will only increase both his profile and his price.