When did the tore in the ligament occur - when he was walking into his hotel or going to the toilet? You are too stupid to realise that he could have not felt it during the match and with heated muscles could survive - a while after completion of play he would have felt the pain stemming from the injury. .
I did say the five-setter was too tough for him because he has won nothing this year and he even lost in Geneva in a ATP 250 tournament . He seems to struggle to even get into quarterfinals this year and never went beyond that to semi-finals. In any event in previous matches he won he was never really convincing during any tourrnament and struggle to win even against non-seeded players.
In th meantime he has lost the no 1 ranking and if Alcaraz win the tournament - af ter his performance against Tsitsipas yesterday that would be very likely - he will end up at no 3. If he does not play in Wimbledon starting in three weeks time he would slip down further in the rankings. Wimbledon start just about three weeks from now and it is likelly that a knee torn ligament will not heal in time for that tournment.
If he does not play at Wimbledon - what touraments remain thei year? First there is the US and Canada tournaments and US Open - after which the emphasis goes back to the European in- door season. He does not qualify yet to play in the EOYC unless he start winning ATP 500 and ATP 1000 tournaments of which there was none up to date. He stand to lose with present performnces to slip totally out of the Top 10 rankings. Not playing or losing early will lead to the following ranking points losses:-
Wimbledon - 1350
US Open - 2000
Paris Open 1000
EOY Championship - 1500
At present he has 8360 ranking points. Not laying or losing early or losing early in torunaments can take him down to 2490 ranking points - which will take him down out of the top 10 rankings to circa 16 to 20 in the rankings. That was what happened to both Federer and Nadal - they ending up outside of the top 600 rankings and signalled the end of their playing careers.
Personally I think Djokovic is not really interested in playing tennis on tournamnet level anymore and as he said himself he will play as long as he is competitive in matches and tournaments - this year he was not really competitive in any tournaments.