The England midfielder – operating again at centre-back alongside new signing Ozan Kabak – went down with a groin injury inside the first half an hour of the 238th Merseyside derby at Anfield.
Henderson initially returned to the pitch after receiving treatment in a bid to carry on, but it was soon apparent that he could not continue and the skipper was replaced by Nat Phillips.
Asked for an update on the injury after Liverpool’s fourth straight home league defeat, manager Klopp said: “It’s the groin/adductor region and nobody in the medical department was positive about it.
“It doesn’t look good, but we have to wait, of course, for the scan tomorrow, hopefully.”
The blow sustained by Henderson continued Liverpool’s rotten luck with injuries during their disappointing Premier League title defence in 2020/21, particulary on the defensive front.
Since Virgil van Dijk suffered a season-ending knee ligament injury in October’s draw with Everton at Goodison Park, the defending champions have been dogged by constant injuries to defenders, with Joel Matip and Joe Gomez also ruled out for the campaign.
Klopp brought in Schalke loanee Kabak and Ben Davies from Preston to help ease that unrelenting crisis during the January transfer window, but despite reinforcing his options the German knows that such a recurring issue is making a tough task for free-falling Liverpool even harder.
“We have options, of course, but how difficult it makes it… it makes it really difficult,” he said. “But, for example, Nat was for sure not for one second our problem and even Hendo in the beginning of the game was really dominant, especially offensively.
“So, yes, it is a massive blow losing Hendo again. Massive. But Nat played a super game. Again, we meanwhile unfortunately got used to it that we have to change things and we just try to set up again for the next game. As long as we have 11 players we will do that.”