"We'll continue to assess Gylfi's progress on a week-to-week basis," Everton manager Sam Allardyce was quoted as saying by the BBC on Wednesday.
Sigurdsson's brother, Olafur Mar Sigurdsson, told Icelandic media the player had damaged the joint of his right knee.
Sigurdsson has scored five of his seven goals in his last 17 matches and his injury is a blow to Everton who are hoping to finish the season on a positive note after a disappointing start.
(This story has not been edited by Social News XYZ staff and is auto-generated from a syndicated feed.)
