Everton are in talks with Southampton fullback Cuco Martina.
The Mirror says Everton have made an approach for Southampton right back Martina, who is out of contract on July 1.
Koeman worked with Martina at St Mary's.
Everton are also monitoring the position of Saint Etienne defender Florentin Pogba, who is the brother of Paul, and has just a year left on his contract with the French club.