Portugal international Vieirinha, 33, sustained the injury in the 1-1 draw at Larissa last week, finding out a day later the severity of the issue, which will likely keep him out of action for at least six months.
But, with a first Super League title in a generation within touching distance, neither PAOK nor Vieirinha allowed the situation to ruin an historic moment.
Already-relegated Levadiakos was the visitor and PAOK made light work of it in a 5-0 thrashing, securing the win it needed to put itself out of Olympiakos's reach.
PAOK raced into a two-goal lead after just eight minutes, before adding another three in the second half in a comprehensive victory.
The comfort of the win allowed for Vieirinha — his right knee heavily strapped up — to enter the pitch in the first minute of stoppage-time.
Right-back Vieirinha, who is in his second spell at the club, was the centre of much of the post-match celebrations despite his difficulty walking.
PAOK's supporters subsequently lit flares all around Toumba Stadium as they waited for the team to re-emerge, with the club crowned Greek champion for only the third time in its history.
Its last title came in 1984-1985.