Tottenham have been told they must pay £36.7m to sign Pedro Porro this month, according to reports.
Antonio Conte is looking to bolster his squad before the January transfer window closes.
The Spurs boss has made acquiring an attacking player and a right wing-back his priorities in the mid-season market, as Conte attempts to lead the north London outfit into the top four for the second season in a row.
Tottenham have identified Porro as their leading target to compete with Matt Doherty, Emerson Royal and Djed Spence on the right-hand side of the pitch.
But Sporting CP would prefer to keep hold of the Spaniard until the end of the season at least.
According to the Guardian, the Portuguese side have told Spurs they must trigger Porro's £36.7m release clause in order to sign him this month.
The 23-year-old, who is valued at £22.1m by Transfermarkt, has excelled in Portugal since leaving Manchester City in 2020.
Porro has scored one goal and provided five assists in the Primeira Liga this season, despite Sporting's general struggles.
Tottenham had been hoping to land him for less than his release clause, but his current employers are demanding the full amount.
After cashing in on Matheus Nunes and Joao Palhinha last summer, Sporting do not need to sell Porro in the current window.
Tottenham beat Portsmouth 1-0 in the FA Cup on Saturday, booking their place in the fourth round of the competition.
They will return to Premier League action against arch-rivals Arsenal in the north London derby this weekend.
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