The Japan international is currently sidelined with an ankle injury.
“It's a shame, we were all really gutted after the (Sunderland) game," Van Dijk said. "I had a similar injury when I was at Southampton, a foot injury, and it's not an easy one to take.
"But we are here for him, we are going to be together with him all the way and support him with everything he needs. It's not great, he is such an important and respected member of the team, he's one of the leaders and he always leads by example as well.
"On the pitch he gives everything and you saw that in the game. It's a big blow but we have to deal with it and we will. Hopefully it's not going to take too long but it looks like it will be a while.”
