Everton boss Marco Silva has blamed rising transfer fees for the club's inability to fulfil their player recruitment targets in defence.
With skipper Phil Jagielka returning to Sheffield United and Kurt Zouma back at Chelsea following the end of his loan spell, the Toffees were keen to bring in a central defender during the recent transfer window.
Silva explained how difficult it was to sign players in the current market and admitted it wasn't ideal that the club couldn't recruit a centre-back to Goodison Park.
"It is really tough now to buy a player – everyone is asking millions and millions and millions,” Silva said in a press conference as his side prepare for a road trip to Crystal Palace.
"It is always difficult to sign players even if you are a big club. Everyone is looking at the final picture and asking ‘why so late signing players?’ But you have to work, and it was a tough market for us.
"OK [having only three centre-halves] is not the best scenario for us. It is what it is. People are just looking at who we sign - but 18 football players left our club.
"I don’t like to speak about those numbers but I know people will say again Everton spent this and this. But in the end, if you put the balance [of players leaving], we spent £28 million ($34m)."
Everton will now enter their Premier League campaign with only three natural central defenders in Yerry Mina, Michael Keane and Mason Holgate.
In addition to Iwobi and Kean, Everton managed to acquire Fabian Delph, Jean-Philippe Gbamin, Djibril Sidibe, Jonas Lossl and signed Andre Gomes permanently - but missed out snaring Palace attacker Wilfred Zaha.
Several first team players departed during the window also, including Idrissa Gueye, Ademola Lookman and James McCarthy.