Manchester United Transfer News: William Carvalho, Joao Mario, Latest Rumours

Manchester United scouts reportedly watched William Carvalho and Joao Mario play for Sporting Lisbon in their 1-0 victory over Moreirense on Saturday.

According to the Sun's Andrew Richardson, the Red Devils have been eyeing central midfielder Carvalho "regularly" in recent years and are looking to make changes for next season.

Richardson added midfielder Mario has only emerged as a United target "in recent weeks."

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Both could be decent additions for United, who look set for another busy summer following a poor 2015-16 campaign under manager Louis van Gaal.

Per Richardson, Portuguese manager Jose Mourinho, who is the favourite to replace Van Gaal in the summer, would potentially "welcome a raid" of Sporting.

Carvalho, 24, has long been regarded as one of the best young defensive midfielders in the world and has performed fairly consistently at a high level this season, per A Bola (via Sport Witness):

With Bastian Schweinsteiger and Michael Carrick getting on in years, United could do with added verve in the middle of the park, and Portugal international Carvalho could provide that.

He will not come cheap, though, as his release clause is reportedly set at £35 million, while Arsenal have also long been linked with him and could battle United for his signature, per Jeremy Wilson in the Telegraph.

Given his relative youth and potential, it would be worth United shelling out more then £30 million for Carvalho as he could be a key part of the Red Devils' squad for years to come.

Mario is also a player who could be a huge asset at United in the future. The 23-year-old has emerged as one of the best midfielders in Portugal this season.

Per FourFourTwo's Tom Kundert, he has contributed to 13 league goals for Sporting (five goals, eight assists) and shown "magnificent control, accurate distribution and faultless decision-making."

His maturity and intelligence mark him out as a top young talent while his work rate is very impressive—see some of his season highlights below:

Like Carvalho, he is a full Portugal international and could be a star at UEFA Euro 2016 this summer.

United could well try to sign him up before the tournament in France, as more suitors will undoubtedly emerge if he shines.