Cape Town - New Everton boss Marco Silva insists that centre-back remains a problem area ahead of Thursday's transfer deadline, with the Premier League season fast approaching.
The Toffees get their domestic campaign underway on Saturday evening when they travel to Molineux to take on newly-promoted Wolves.
Silva has so far added two players to his squad since replacing Sam Allardyce at the helm on May 31, with Richarlison joining from Watford, while Lucas Digne was coaxed away from Barcelona.
However, Ashley Williams has since departed for Stoke on an initial season-long loan, leaving the Portuguese coach with a severe shortage in central defence due to Mason Holgate's injury at the start of pre-season.
The Merseysiders have been linked with Barca defender Yerry Mina and Newcastle captain Jamaal Lascelles, with Silva stressing that reinforcements are desperately needed.
"It is not the best thing to do to wait until the last days but the market is really difficult," he said. "When we started we knew more or less what were our targets.
"I know what positions I have to improve and I have started to make more decisions to be sure about everything. But in some positions it was clear in my mind what we needed from the first day.
"Since the first day if I want to put one central defender in the game we don't have any. Mason Holgate has been injured since the first week of pre-season.
"We lost others [Ashley Williams]. It is one position and it is easy to understand how many we need in that position. We have to sign new players there.
"It is not easy for us as a club to sign some players because in normal situations they ask a lot of money and also we have to make the right decisions. We have to really improve our squad."