Liverpool are also sweating on the fitness of striker Mohamed Salah, who picked up a groin injury on international duty with Egypt while fellow forward Sadio Mane is a major doubt after having hand surgery.
"We had yesterday's session and a few of the boys trained. We have to see how they reacted after that. It's pretty sure that Naby will not be available. With the rest we have to see how it develops," Klopp told a news conference.
Defender Van Dijk missed the Netherlands' 1-1 friendly draw with Belgium last week, still struggling with a rib injury that he suffered against Southampton last month.
"Virgil would not leave a game without any major problems but it's settled quick and that's how it is," Klopp added.
"Football players have to play very often with some kind of pain, that's how it is. It's all good, he has no problems with that anymore."
Third-placed Liverpool are looking to extend their unbeaten start while Huddersfield, managed by Klopp's former team mate at Mainz David Wagner, are winless and in the bottom three.
However, the German said Liverpool would be wise not to underestimate their rivals.
"Our analyst said they're stronger than you can imagine. That's why I use the word 'trap'... There will be an outstanding atmosphere and we need to be ready," Klopp said.
"It will not be an easy game, it will be the opposite. If we do our best, and do what we are good in, it will be difficult for Huddersfield. That is clear."
(Reporting by Shrivathsa Sridhar in Bengaluru; editing by Martyn Herman)
