The Croatian missed Tuesday's Champions League semi-final first leg draw at Real Madrid, but is in contention to return to the squad for Premier League duties.
If Kovacic does feature, though, it will probably be from the bench.
With Zinedine Zidane's side making the trip to London this midweek, Thomas Tuchel may consider resting a few key players.
Fulham are winless in five games and currently find themselves seven points adrift of safety.
Expect 36-year-old Thiago Silva to sit this one out and Kurt Zouma to replace him alongside Antonio Rudiger and Andreas Christensen.
Captain Cesar Azpilicueta should maintain his place at right wing-back opposite Ben Chilwell, although Reece James and Marcos Alonso are also available for those spots on the flank.
Kai Havertz and Hakim Ziyech could be kept back for Madrid depending on what XI Tuchel is considering for that one, but Timo Werner is likely to start up front with Christian Pulisic and Mason Mount again.
N'Golo Kante and Jorginho will keep their places in midfield, with Kovacic unlikely to be thrown back in.