Cape Town - Everton have announced that Ramiro Funes Mori and Ross Barkley will not be available for the start of the new season after both players underwent surgery.
Mori's knee had to be operated on for a second time due to complications the 26-year-old defender suffered after tearing his meniscus in March while on international duty with Argentina.
Barkley went under the knife to cure a groin complaint that had kept him out of the club's pre-season tours to Tanzania and the Netherlands.
The 23-year-old playmaker, who has been linked with a move away from Goodison Park during the current transfer window, is expected to be out of action for the next four weeks.
Mori is of greater concern, however, as the Argentine will sit out a large chunk of 2017/18 with a timescale on his comeback set between six and nine months.
Ronald Koeman's side open their Premier League campaign at home to Stoke City on August 12.