The Reds' top goalscorer fell awkwardly after a tangle with Leighton Baines in last Saturday's Merseyside derby against Everton, having attempted to block the left-back's clearance. That left him with damage to the meniscus in his left knee.
Swelling had initially been inconclusive Mané was sent for scans but now it has subsided, the full extent of the issue has been revealed and that 24-year-old has been dealt the blow that he will not play again this season.
The Senegal international having been involved in more league goals than any other Liverpool player, with 18, since his £30 million move from Southampton last summer - Klopp acknowledged the disappointment of his lay-off.
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He revealed in his pre-match press conference ahead of Saturday's trip to Stoke City that the club are "pretty sure" that Mané will need surgery and added: "I am not 100 per-cent sure when it [the operation] will happen but then it is clear his season is over."
The German admitted it is what he "half-expected" after seeing Mané shortly after the victory over Everton and watching footage of his injury, suggesting that the wide-man was "lucky in this situation that not more happened."
"But we are close enough to the end of the season to say that it will be pretty much impossible to play again this season," Klopp continued to reporters.
The only positive news that the Reds boss took away from the situation is that it means Mané "will get a longer break and will be ready for next season", which he called "the only good news."
The Reds' No.19 will miss all of their final seven games of the season, including the clash with Stoke at the bet365 Stadium this weekend, having already missed the 2-2 Anfield draw with Bournemouth in mid-week.
The Merseyside outfit had harboured hopes that Mané could avoid a surgical procedure and feature again before the end of the season, but Klopp will instead have to look to his other attacking options as they hope to hold on to a top-four spot.