Spaniard Garcia was taken to hospital after he fell to his knees clutching his face just before the kickoff.
Olympiakos officials pulled their players off the pitch in protest and later said Garcia was being kept in hospital overnight as he was suffering from an "internal bleeding of the lip".
More than 2-1/2 hours after the scheduled kickoff, the match was called off as fans clashed with police outside the stadium.
Police used tear gas to disperse the angry crowd who were rioting in the surrounding streets.
According to Hellenic Football Federation regulations, Olympiakos are expected to be awarded a 3-0 victory. PAOK face a three-point deduction, can be fined up to 90,000 euros (£79,118) and ordered to play two matches behind closed doors.
The punishment will be a huge setback to PAOK's title hopes as it means their six-point lead over third-placed Olympiakos will disappear and both teams will be left on 49 points.
However, Olympiakos also face a three-point deduction following clashes in their match against AEK on Feb. 4 and will learn the result of their appeal on Thursday.
(Editing by Pritha Sarkar)
