Lucas Digne has suffered a knock to his ankle in training which could keep him out of action for up to two months, according to France Football.
The report suggests that the Frenchman, 27, sustained the injury at Finch Farm this week and disappointing early scans revealed a need for him to undergo surgery in the coming days.
It is a bitter blow for the left-back, who has started the season in blistering form, with four assists in eight Premier League games - including two in Sunday’s 3-2 win at Fulham.
And a two-month layoff would rule Digne out of a particularly hectic winter schedule, which includes Everton’s clashes with Chelsea, Leicester City, Arsenal, both Manchester clubs and Wolverhampton Wanderers, as well as a possible EFL Cup semi-final in early January.
Niels Nkounkou may step up in Digne’s absence as Everton’s only other natural left-back, but the 20-year-old has had just one Premier League outing since his summer move to Goodison Park.
Fabian Delph, though naturally a central midfielder, can also deputise at left-back, having played there for much of Manchester City’s 100-point season under Pep Guardiola in 2017-18.
Lucas Digne - Everton games he could miss
Sat, Nov 28 - Everton vs Leeds
Sat, Dec 5 - Burnley vs Everton
Sat, Dec 12 - Everton vs Chelsea
Wed, Dec 16 - Leicester vs Everton
Sat, Dec 19 - Everton vs Arsenal
Wed, Dec 23 - Everton vs Man Utd (EFL Cup quarter-final)
Sat, Dec 26 - Sheff Utd vs Everton
Mon, Dec 28 - Everton vs Man City
Sat, Jan 2 - Everton vs West Ham
Jan 5/6 - EFL Cup semi-final
Sat, Jan 9 - FA Cup third round
Tue, Jan 12 - Wolves vs Everton
Sat, Jan 16 - Aston Villa vs Everton
Sat, Jan 23 - FA Cup fourth round
Tue, Jan 26 - Everton vs Leicester