Everton are consulting with experts throughout Europe as they consider the best course of treatment for midfielder Jean-Philippe Gbamin's thigh injury.
The £25million summer signing has initially been ruled out for up to eight weeks after assessment revealed he had sustained a tendon injury in the quadriceps of his right leg.
However, it is understood Everton have not ruled out surgery for the Ivory Coast international, whose only start so far this season was in the 1-0 win over Watford on August 17.
"It's something we didn't expect after we saw a muscle injury," head coach Marco Silva told a press conference ahead of Everton's Carabao Cup trip to League One Lincoln.
"But the scan gave this feedback for us and now it's a matter for us to try and get the player ready again as fast as we can.
"For the moment we can talk to you about between six to eight weeks, it's the type of situation we have to see day by day.
"But, in this moment, that's the target we have for him."
There was better news for Silva over another summer signing Fabian Delph, brought in from Manchester City for £8million to add some much-needed experience.
He has been declared fit after being sidelined by a groin problem in pre-season but he is not a like-for-like replacement for Gbamin.
"He can give different options to me in a technical point of view, he can give very good things for us in important moments of the game with his experience," added Silva.
"When you lose one player like JP (Gbamin), you are talking about a completely different football player.
"JP is a clear number six. Of course Fabian can do that also but he's not that profile as a player."
Everton played Lincoln, then a League Two club, in the third round of the FA Cup in January and laboured to a 2-1 victory.
On that occasion Silva left out key players Seamus Coleman, Andre Gomes and Richarlison but he refused to talk about how many changes he would consider at Sincil Bank.
"We have maximum respect for our opponent and the competition. It doesn't make sense to make rotation just to make rotation," he said.
Summer signings Moise Kean and Alex Iwobi could both make their first starts against the Imps.
