Everton are planning to make a late swoop for Dutch international Bruno Martins Indi.
The Independent reports that Stoke are keen to sign the defender permanently after he impressed whilst on loan at the club last season.
Stoke did have the option to sign the defender permanently for £8 million at the end of his loan deal, but the clause in the contract expired on 1 July, meaning Porto could potentially demand more money.
The defender is believed to be involved with Porto’s pre-season tour of Mexico, which could delay talks over his next move.
Everton have already signed Michael Keane this summer and have also been linked with a move for Virgil van Dijk, although, the latter is likely to be too expensive for the Toffees.