Liverpool captain Jordan Henderson fears the groin injury he picked up in the recent 2-0 defeat to Everton could keep him on the sidelines for a number of weeks.
Deployed as a centre back for the sixth game in a row, Henderson managed just 29 minutes of the game before going down with the injury - the fourth time the England international has picked up a problem this season.
After the game, Klopp described Henderson's predicament as 'not good', and those concerns have been backed up by The Times, who note that initial scans have already effectively ruled him out of the Champions League last 16 second leg against RB Leipzig on March 10.
Henderson is also fearful that he may be out for even longer and his place in Gareth Southgate's England squad for the World Cup qualifiers at the end of March may be in doubt.
Southgate's side face San Marino, Albania and Poland between March 25 and 31, but Henderson is concerned that he might not be back in time to feature, or at least not with enough time to prove his fitness beforehand.
However, while Southgate has a huge talent pool from which to pluck an alternative to Henderson, Klopp does not have that same luxury and will be devastated to see yet another emergency defender ruled out with an injury.
First reserve Fabinho has also been out with a muscle injury in recent weeks, leaving Henderson to play alongside January signing Ozan Kabak.
Klopp opted to bring on young Nat Phillips following Henderson's injury, snubbing new arrival Ben Davies who is yet to appear for Liverpool since joining from Preston North End in a deal worth in the region of £1.6m.
The boss' third and final option is 20-year-old Rhys Williams, who could well feature in some capacity in Liverpool's next game, a visit to Bramall Lane to face Sheffield United on February 28.
Klopp will hope that the return leg against Leipzig will not be too problematic for his side, who roared to a 2-0 win away from home in the first fixture. However, with his defence so stretched and Liverpool in such a tricky patch, the boss will definitely not take anything for granted.