The Ghana midfielder has played just once since his summer switch to Craven Cottage and hasn't featured since the win at Sunderland on the opening day of the season.
Jol reasoned: "On the bench I have to make decisions, like can they play in different positions.
"Derek wasn't even in the 18 for the last game.
"He didn't play for a year and it showed. He was good in the first hour [at Sunderland] and then he dropped a bit."