William Osula of Newcastle United battles for possession with Enzo Fernandez of Chelsea during the Carabao Cup Round of 16 match between Newcastle United and Chelsea at St. James's Park in Newcastle. [AFP]
"I like to say there are players that are fantastic, but for me we don't have indispensable players," said Maresca.
"If Cole (Palmer) is not playing for any reason, we play Joao (Felix). If Nico (Nicolas Jackson) is not playing, we play Christo (Christopher Nkunku). There is not one that we cannot change.
"The reason we change players is because we think that all of them are good. Some of them are better than the rest, but it doesn't mean they are always the ones that are going to play."
Reports in Spain have suggested Real Madrid could move for Fernandez in a cash-plus-player deal.
But Maresca, whose side face Manchester United on Sunday, said Lavia and Caicedo had not locked down the midfield.
"It's a matter of balance," he added. "Romeo and Moises give us physicality, strength in the middle.
"When we play with Enzo it has to be him and one between Moises and Romeo, and when Enzo moves we struggle a bit in the middle in terms of physicality. It's something Moises and Romeo give us."