Jordan Henderson set to be ruled out until February with hamstring problem after scan revealed the extent of the Liverpool midfielder's injury
The England international damaged the hamstring in his right leg during Friday's 3-3 draw with Arsenal.
Henderson underwent a scan and the tear in the muscle is grade two level, meaning he will be absent for the next four weeks at least - ruling him out of six games including the FA Cup third-round clash with Everton at Anfield next week plus the League game with Manchester City on January 14.
It is understood Liverpool's captain is distraught over the setback, as it could not have come at a worse time. He knew something was wrong when he pulled up sharply at The Emirates and is resigned to now beginning a period of rehabilitation.
Klopp is just as frustrated as Henderson by the setback as he believed the midfielder - who has suffered varying injuries over the past two seasons, including a broken metatarsal and damaged medial ligaments - was getting close to his peak form.
He will, at least, be ready for the Champions League last-16 tie with FC Porto in February.