The Red Devils have been linked with the 21-year-old for some time and are believed to have had scouts present at his side’s 0-0 weekend draw with Academica to further assess his abilities.
Despite splashing a club record £37.1m last month to land Juan Mata, David Moyes is believed to have substantial funds at his disposal for the next transfer window, and is already planning a major overhaul of his squad.
The Scot sees his midfield as a major source of concern, with physical presence and energy in short supply.
Carvalho has been hailed for his bombarding displays in Lisbon, and is being touted as a future star at a senior international level.
Like many young enforcers, he has been compared to former Arsenal hero Patrick Vieira thanks to his rangy passing and powerful playing style.
The starlet certainly won’t come cheap, with Sporting having inserted a £37m release clause into his contract.
Despite being in a state of financial worry, the Portuguese giants may be reluctant to sell for anything lower than that value, with their player tied down until 2018.