The Blues are reportedly eyeing a move for the Sporting Lisbon midfielder.
The Blues are expected to be busy in this transfer window as manager Ronald Koeman looks to use the funds made available by Farhad Moshiri.
Only goalkeeper Maarten Stekelenburg has arrived at the club so far, although it is likely a list of potential targets has been discussed with new Director of Football Steve Walsh.
A central midfielder appears to be one of his priority targets, with the club having been linked to several so far this summer.
And according to Portuguese newspaper Record, Sporting Lisbon midfielder Adrien Silva has been added to their list.
The newspaper states that Everton are yet to make a move for his services, but that they could be willing to pay as much as £21 million to secure a move.
He is not the only Sporting player they are interested in though, with William Carvalho having been linked for much of the summer and Record stating he is also among their potential targets.
It remains to be seen if they will make a firm offer for either as Koeman steps up his transfer business ahead of the new season.