Lukaku ruled out for "weeks"
Everton striker Romelu Lukaku is likely to be out for "weeks rather than months" with an ankle injury.
"There is no ligament damage and the injury is not as bad as we first thought," Martinez told evertonfc.com.
"It will be a case of weeks rather than months."
Lukaku has scored nine goals in 20 appearances since joining on loan from Chelsea in the summer.
"We are aware of a significant number of complaints regarding queue management from supporters waiting to enter Anfield at last night's derby match," said director of communications Alan Myers.
"The club will make contact with Liverpool Football Club to raise these matters."