Isak has been absent with a toe injury that was made worse by attempts to play through the pain.
He missed both the 1-1 draw with Manchester City and the Carabao Cup win over League Two side Wimbledon.
Asked about the issue on Monday, manager Eddie Howe stated: "It was one of those situations where, if Alex could tolerate the pain, he would be fine.
"He tolerated the pain for about 80 minutes (at Fulham) before he became aware of any feeling back in that toe. It was either he’d be out until probably after the international break initially, or he could carry on playing as normal if he could tolerate the feelings and the effects of the injury. He hasn’t been able to do that, so we’re back to the original diagnosis, I think.
"We're sort of assessing him on a daily basis because there is a chance he could be fit for Everton if everything falls into place. Of course, then we have a decision to make. Does he play in that game or do we leave him knowing that he'll be OK two weeks afterwards?"