
The 23-year-old, who signed in the close season from Bundesliga side Mainz 05 for a fee reported to be around £25 million (US$31 million), suffered a tendon injury and did not play a part in the 2-0 loss to Aston Villa last week.
“Jean-Philippe Gbamin has sustained a tendon injury in his right quadriceps muscle, which will keep the midfielder out of action for at least eight weeks,” Everton said in a statement.
“The full timescale for the injury will be established following further investigations this week.”
Everton, currently 12th in the standings, play League One (third-tier) side Lincoln City away in the second round of the League Cup on Wednesday.