Gylfi Sigurdsson has been Swansea's outstanding player this season. David Davies/PA Images via Getty Images

Everton are exploring the possibility of a summer move for Swansea midfielder Gylfi Sigurdsson, sources close to the Merseyside club have told ESPN FC.

Everton are planning to spend in the window as they look to keep pace with the top six in the Premier League, and Sigurdsson figures highly on their wanted list.

He has been Swansea's star performer this season, contributing nine goals and 11 assists in the club's fight for Premier League survival.

Sigurdsson, 27, is regarded as one of the best attacking midfielders in the Premier League and Everton boss Ronald Koeman sees him as a player who can add creativity next season.

Swansea will be determined not to lose the Iceland international but would find it almost impossible to keep him if they suffer relegation to the Championship.

He could be a ready-made replacement should Everton lose Ross Barkley, with the England international entering the final year of his contract at Goodison Park.

Premier League clubs including Tottenham have been credited with an interest in Barkley.