The summer signing returned to the side for Tuesday night’s Champions League semi-final first leg, but was withdrawn after just 18 minutes at Anfield.
As Liverpool mounted an intense start in a remarkable atmosphere, Oxlade-Chamberlain snapped into a brilliant, fierce challenge on Roma left-back Aleksandar Kolarov.
Winning the ball cleanly the 24-year-old then buckled under the tumbling Serbian, writhing in pain near the touchline and requiring a stretcher off the field.
“It looks like [his season is over], unfortunately,” he told reporters at Anfield.
“We don’t know it exactly but if the medical department is quite concerned without a scan then you can imagine it is difficult.
“The season is not that long anymore, so it doesn’t look good. I am a very positive person and still hope that he only ‘feels’ bad and is not that bad, but we will see that.
“I see in your faces, maybe you are a little bit surprised I am not flying, mood-wise.
“It’s just we lost a fantastic player tonight and that is not good news, so I am not really in the mood to talk about specific, fantastic things.”
With just three games left to play in the Premier League and likely two more in Europe there is little opportunity for Oxlade-Chamberlain to recover in time to feature.
Stoke City visit Anfield for another league clash on Saturday, and Klopp is now left to decide whether to persevere with Wijnaldum, James Milner and Jordan Henderson or, as he told BT Sport, “get creative.”
Otherwise, the recent return of Ben Woodburn could see the Wales international take up a pivotal role on the domestic stage in the coming weeks.
Herbie Kane is another option from the youth ranks, but the Liverpool squad is certainly thin at a vital period.