The Brazilian midfielder has struggled with an adductor injury all week which has prevented him from taking part in training and could mean he misses the visit of the Terriers. He will be assessed before the club make a final decision.
Coutinho's injury presents a potential selection dilemma for Klopp, who is already without winger Sadio Mané, midfielder Adam Lallana and right-back Nathaniel Clyne - all of whom would likely start if fit.
The 25-year-old has - expectedly - been a key influence since his return to the team, contributing four goals and three assists in his last six games in all competitions.
And he would be a huge miss if ruled out as the Reds go in search of a much-needed three points against David Wagner's charges, who overcame Manchester United to claim a huge victory last weekend.
Liverpool suffered a heavy defeat at Tottenham Hotspur in another early setback - one which leaves them 12 points off Premier League leaders Manchester City after only nine games.
Reds uncertain over Coutinho fitness
Klopp told his pre-match press conference that it is "not clear in the moment" whether Coutinho will be available to face top-flight newcomers Huddersfield or not.
He added: "Last week he had some back problems before the Tottenham game, but then during the week it settled with treatment and all that stuff, so he was fit for the game."
The German revealed that Coutinho has "had a little bit of a problem with the adductor" throughout this week and that it is "not clear so far if he is out" for the visit of the West Yorkshire outfit.
"We will make the decision today after training," Klopp said on Friday, insisting that the No.10 "didn't train yesterday" but that it is "all for the moment" and a decision will be made.
Liverpool are also without winger Sadio Mané, midfielder Adam Lallana and right-back Nathaniel Clyne but Klopp continued: "There are no other news things [injury issues]."