William Carvalho has been a Premier League target for years but will be harder than ever to sign this summer after becoming a pawn in the war between Sporting Lisbon president Bruno de Carvalho and Jorge Mendes.

De Carvalho came to power promising to end Mendes’ influence at Sporting, meaning that their players could no longer be represented by the most powerful agent in the game, who is now persona non grata at the Estadio Jose Alvalade. “I did great business last summer without his help,” De Carvalho said confidently in Lisbon yesterday.

William Carvalho, a powerful defensive midfielder, was one of Mendes’ crown jewels at Sporting, along with Joao Mario, Adrien Silva and Rui Patricio. Carvalho, until last year, was stuck on the youth contract he signed as a boy at Sporting, earning a annual net salary in the region of just €50,000. But he was priced out of a move by a €30million release clause. Arsenal and Monaco thought very seriously about signing him in 2014, but eventually decided against it.

Sporting refused to negotiate a new contract with Carvalho, though, for as long as he was represented by Mendes. It was only when he left Mendes, in February of this year, that he could sign a new contract at Sporting with a long overdue pay increase to €1m salary. That contract, though, came with a €45m (£40m) release clause that is threatening to price him out of a move to the Premier League.

Plenty of Premier League teams are aware of Carvalho, who was the best player at the European Under-21 Championship in 2015, and then part of Portugal’s victorious team at Euro 2016. West Bromwich Albion bid £21m for him on the penultimate day of the summer transfer window, but Sporting rejected the move out of hand.