Manchester United are reportedly considering triggering the €50m (£44.7m) release clause of Porto defender Eder Militao.
Jose Mourinho is desperate for defensive reinforcements during the January transfer window, having seen his side miss out on all of their targets this summer.
Militao is understood to have been earmarked as a possible target, but The Times reports that United would need to pay his full release clause to prise him away from the Estadio Do Dragao.
The 20-time champions of England are looking at a number of players, including Kalidou Koulibaly, but could turn to Militao after being quoted £90m for the Napoli centre-back.
The Brazilian is unlikely to come cheap himself, though, with his current Porto deal not expiring until 2023 and Porto reluctant to lose one of their star players.
Militao, 20, has made 14 appearances for the club across all competitions this season, scoring one goal.