With the World Cup less than seven weeks away and the deadline for countries to name final squads around five weeks away, any sort of injury that isn't a very minor damage will leave 24-year-old Oxlade-Chamberlain's chances of going to Russian Federation in very serious doubt indeed.
Oxlade-Chamberlain, signed from Arsenal a year ago, will miss the conclusion of the Reds' Champions League run, as well as the World Cup finals, but he is trying to stay positive ahead of a lengthy lay-off.
The Liverpool midfielder came off injured in Liverpool's 5-2 win over Roma in Anfield on Wednesday night.
"Oxlade-Chamberlain's is probably a really bad injury", the German told BT Sport.More news: Beijing will continue to support Pakistan: Chinese vice president
England begin their World Cup campaign against Tunisia on June 18.
The 24-year-old midfielder was assessed on Wednesday and Liverpool said he will not return to full fitness until next season.
He scored his first goal for the club in the team's 7-0 drubbing of Maribor in the group stages of the Champions League. Oxlade-Chamberlain was carried off on a stretcher in the 18th minute of the first leg at Anfield on Tuesday. With Emre Can and Adam Lallana also sidelined indefinitely, Klopp has just three fit traditional central midfielders remaining in Jordan Henderson, James Milner and Georginio Wijnaldum.
His absence will no doubt be seen as a huge blow for both Liverpool and England going forward and it will be devastating news for the former Southampton player missing one of the most crucial periods of his career.