Everton midfielder Jean-Philippe Gbamin is set to be sidelined for around three months after undergoing surgery.
The 24-year-old has played just twice for the Toffees since arriving from Mainz in the summer, with his last outing coming against Watford in August.
An Everton statement read: "Everton Football Club can confirm that Jean-Philippe Gbamin has undergone surgery on a tendon injury in his right quadriceps muscle, which will keep the midfielder out of action for around three months.
"The 24-year-old had returned to light training at the start of this month but suffered a setback in his rehabilitation. As a result, the summer signing from Mainz underwent surgery in France on Tuesday."
The Ivory Coast international arrived at Goodison Park for a reported £25million at the start of August.
He made his debut for Marco Silva's side as a substitute versus Crystal Palace, with his first start arriving a week later against Watford.
Everton had hoped Gbamin would be able to avoid surgery, but his absence adds to the problems facing Silva whose side sit in the relegation zone after a poor start to the season.
