The Everton manager initially speculated that the 20-year-old could miss up to five months of the season, but now says he has responded well to treatment.
Everton coach Roberto Martinez has denied that midfielder Ross Barkley will miss five months with a knee injury suffered in training Friday.
Martinez previously said the England international could be "out for a long, long time" and that it's the type of injury that could take "between seven weeks and four and five months."
"His knee has reacted really well to treatment," Martinez told the club's official website. "I don't know where the figure of five months came from but obviously the extent of the injury is a little unsure at the moment because we don't know how the next two weeks are going to develop.
"It's a medial ligament injury and we know that Ross, in terms of the power and the strength that he has in his body, he could easily react to treatment a lot better than other players. The length that Ross will be out is a little uncertain at the moment and it could be anything between the eight weeks that we mentioned or a little further.
"Until the end of the week, or probably the next 10 days, we won't know how the knee is progressing and how quickly Ross can be back."
Martinez added that further updates on Barkley's condition could be expected in the coming days.
Better news surrounds the fitness of Seamus Coleman, who is now ready to start games after overcoming a hamstring issue, while Martinez also said that Darron Gibson [knee] is progressing well.
"Seamus was fully fit from a medical point of view on Saturday [in the 2-2 draw with Leicester City] and that was a real boost," the Spaniard said. "He has been working really well, and he was desperate to be part of the squad on Saturday. I think now it's fair to say that he's considered fully fit and ready to join the group and help the team in any game.
"Darron is working really well and is building some better fitness levels. We need to make sure after a long spell on the sidelines that all the work we are doing is allowing him to be fully fit. It's going to be a very, very busy period in September and everything is working towards that month where Darron can be fully fit and he can have a really good period on the pitch, so it's not a problem at all with Darron."