Everton manager Ronald Koeman is looking to sign the Southampton defender Cuco Martina on a free transfer this summer.
The Saints have decided to release Martina along with Isgrove, Willard and Caceres.
According to Liverpool Echo, Koeman tried to sign the former Twente defender last summer but Southampton refused to sell the 27-year-old back them.
Everton right-back Seamus Coleman has sustained a long-term injury and Holgate is expected to play as a centre-back next season. Therefore, Koeman needs another right back in order to fill the void.
Koeman wants Martina to be his first summer signing and according to the report, the defender has already been flown to Merseyside.