Southampton boss Ronald Koeman has no idea what to expect from Europa League opponents Vitesse Arnhem.

Koeman insists it's impossible to plan for Vitesse due to their relationship with Chelsea.

"Because of their association with Chelsea they change players every year," said Koeman.

"They have already lost a lot of good players now."

Koeman knows Vitesse will be strengthened by Chelsea loan players, but believes it will take time for them to bed down.