It has been reported that Mane suffered a broken left thumb while on global duty with Senegal, with the forward injuring his hand in their Africa Cup of Nations qualifier against Sudan.
Salah and Van Dijk withdrew from their national teams over the worldwide break amid fitness concerns, but trained at Melwood on Thursday afternoon.
The Reds boss confirmed a blow with the news that Naby Keita is expected to miss the game tomorrow afternoon after suffering a hamstring injury while away on worldwide duty with Guinea earlier this week.
Specifically on Van Dijk, who featured for Netherlands in a victory over Germany last Saturday before returning to Melwood and sitting out his country's draw with Belgium, Klopp insisted there were no long-term concerns over his recent rib injury.
There remain doubts surrounding Mo Salah and Sadio Mane with both carrying minor knocks but neither have been ruled out of the game at the John Smith's Stadium according to the German manager.
Harry Wilson reveals Jurgen Klopp messages, talks Frank Lampard influence
There are a lot of new faces, it's a re-building thing but at the same time we have a lot of positive players as well. We'll also stream our commentary on our YouTube channel which you can alos listen to at the top of this article.
Keita sustained the issue while playing on an artificial surface for Guinea in Rwanda on Tuesday.
Huddersfield boss David Wagner celebrates his 47th birthday on Friday but Reds boss Klopp will not be giving him a gift.
"Obviously he knows that he needs to try and do a little more than he is doing right now but he's giving his all and I'm not anxious at all".
"Now we have a great opportunity, a wonderful game in front of our fans against a very strong side, where we can hopefully perform at the same level [as our last game]". We can watch the games but what they do in training you cannot know.
Information from Reuters was used in this story.