Wantaway Blackburn central defender Christopher Samba is to go into hospital for tests after falling ill ahead of the club's superb win over Fulham.
Rovers manager Steve Kean confirmed on Saturday, after a 3-1 victory at home to the Cottagers achieved with only 10 men after Ayegbeni Yakubu's 23rd-minute dismissal, that Samba then claimed to be sick on Friday morning.
"He trained really well all week, but then he texted the doctor on Friday to say he was not feeling well," said Kean. "That was really disappointing because he would certainly have been available to play.
He added: "So he'll be at the hospital either [on Saturday night] or [Sunday] morning, just for tests because he has complained of severe stomach cramps. We'll make sure the virus he has is not too serious, that it clears up and he can be available for Everton."
After Yakubu saw red for the first time in his nine-year English football career for a high, studs-first challenge on Danny Murphy, it was Rovers who took the initiative.
Morten Gamst Pederson scored with virtually the last kick of the first half with a 20-yard free-kick, with David Dunn netting his first goal since February 5 last year just 56 seconds into the second period.
Although Damien Duff pulled one back soon after, substitute Mauro Formica settled matters in the 79th minute to lift Rovers out of the bottom three for the first time in four months.
For Fulham, it was only their second defeat in their last eight games, pulling them to within six points of the relegation zone, and Jol said: "It looked like everything was going for us, but then we conceded a goal just before half-time, which is not what you want.
"We tried to repair the damage, but then they scored a second early in the second half, which we couldn't do anything about.
"We pulled one back, but when they got their third it was over, so all credit to them."