Ake has been one of the most consistent performers for the Cherries in recent seasons, earning him a call-up to the Dutch national team.
"First of all, he's a fantastic guy," Van Dijk told the Daily Echo.
“I speak with him quite a bit at the national team and I think he's a fantastic player as well.
“On Saturday he showed with clearances and I think he stepped up when he had the armband as well. It's just good to see that he's improving.
“I don't know what might happen with him in the future with Bournemouth, you just have to stay grounded – but I am not worried about that at all.
“He has the quality but he has to have more than just the quality these days. But he's still young, he's improving and you never know what decision might happen.
"It's all dependent on how the season will end for Bournemouth, too – but I am very positive about him. He's a fantastic guy and player as well."