Press Association Sport understands the 25-year-old damaged the lateral collateral ligament (LCL) in his left knee during Thursday’s 1-1 Europa League quarter-final first-leg draw in Dortmund.
Henderson underwent a scan in Liverpool following the team’s return to Merseyside on Friday lunchtime to determine the extent of the injury.
While there is some positive news for the player in that it is an LCL problem and not a cruciate ligament, which is far more serious, and there is limited damage, it is still likely to sideline him for six to eight weeks – a typical LCL injury can often require three months’ recovery.
However, Henderson will not require surgery, just treatment and rehabilitation.
England coach Roy Hodgson will name his Euro 2016 squad in less than five weeks’ time on May 12, three days before the end of the Premier League season, with their first warm-up against Turkey on May 22.
Even in a best-case scenario, Henderson would only be close to a return by that later date but severely lacking in match fitness and it would represent a major gamble on Hodgson’s part to pick the midfielder, one it seems he is highly unlikely to take.