The 26-year-old had angled for a move to Anfield during the summer but Southampton held firm.
"I don't think it will be difficult because Virgil knows he is focused 100 per cent on our team and is training well," he said.
"He wants to improve his performances because obviously he was injured in (January) and then he didn't play any games."
"Obviously we cannot control the (transfer) market and every single transfer window clubs are looking to buy our players.
"But we are looking for players to try to improve our squad too. It's part of our job.
"Football today is a big business - and we have to understand this. Now clubs are fighting in the market to find the best player and we have a lot of good players - it's part of our job.
"It's no secret that sometimes players are distracted but it's normal."