Fulham boss Martin Jol fears Bryan Ruiz may have suffered a broken metatarsal in the win over Bolton.
The Costa Rica ace was forced off in the second half at the Reebok Stadium with a foot problem.
Jol is now waiting to find out the full extent of the injury with the forward definitely out of Monday's clash with local rivals Chelsea.
"It is worrying - he has probably broken his metatarsal. That is a problem."
If Fulham's worst fears are confirmed Ruiz will miss the remainder of the season for the Cottagers.