The club has announced the 23-year-old is visiting his native Belgium to see a doctor over the issue.
Lukaku to sign Everton deal - agent
However, the Toffees are confident Lukaku’s injury is not serious and he will be fit for their next Premier League outing against rock-bottom Sunderland on February 25.
The only other first-team player missing from the trip is Yannick Bolasie, who is a long-term absentee with a knee injury.
Lukaku has been in superb form this season, scoring 16 goals in 24 league outings - a return bettered by only Arsenal’s Alexis Sanchez.
