Van Dijk, 27, missed his team's cup defeat to Chelsea due to a rib injury and is in doubt for the blockbuster Premier League clash between the sides on Saturday.
Klopp is yet to decide if the Netherlands international will feature, as Liverpool head to Stamford Bridge looking to maintain their perfect start to the league season.
But the German seemed somewhat upbeat about Van Dijk's chances of playing.
"I will decide if he plays. If the player goes out and says, 'No chance', then I cannot decide, but in all other situations I will decide," Klopp said.
"Virgil will try everything to be ready and I know how this sounds but as long as you are not seriously injured, like something broken or ruptured or a proper strain, then the boys play constantly with pain.
"And if you have no pain before the game then you will have it after the first challenge. That is how football is.
"It is important how you deal with the pain and how strong is the pain, but if he is able to deal with it then he can play."
Liverpool are two points clear atop the table ahead of their trip to Stamford Bridge, but will come in knowing that Maurizio Sarri's side got the better of them earlier in the week.
And, while Klopp is wary of Eden Hazard ahead of Saturday's clash at Stamford Bridge, the German said it was too tough to man-mark the 27-year-old attacker.
"When Dortmund played Real Madrid [in the 2013 Champions League semi-final] I played Mario Gotze against Xabi Alonso but no, I will not man-mark Hazard, because he is much more flexible," he said of taking special precautions against the Belgian star.
"He is all over the park. With Xabi Alonso it was clear where he was playing. That is a big difference.
"I have the biggest respect for this player. I love it, what a player, but it is not to defend alone.
"Yes it is difficult, but we have to do all the things around it: close spaces, make passes more difficult."