Southampton boss Mauricio Pochettino has warned Maya Yoshida not to relax.
Pochettino has brought in fellow centre-half Dejan Lovren from Lyon this summer.
"I want all of my players to play a big role within this club but unfortunately that's not possible, so all of them will have to earn their position. I wish the best for Maya and the rest of my players," said Pochettino.
"At the moment he is on holiday as he was playing for the four weeks during the Confederations Cup. After Brazil we gave him a medical check and saw that he was not completely fit, but he still has ten days of holiday left."