Vaillancourt, who is facing a dozen charges including fraud and gangsterism, was not present Wednesday in a courtroom north of Montreal.
All of the evidence should be divulged to Vaillancourt and 36 co-accused before they return to court on Oct. 1.
Judge Gilles Garneau advised lawyers that all the accused will be expected to attend that hearing to determine the next steps in the case.
The others charged in the massive corruption sweep include former Laval bureaucrats, construction executives and engineering bosses.
Crown prosecutor Claude Dussault says he expects a megatrial involving all the suspects.
"They are charged in the same case so we can assume for the moment that everything will proceed at the same time," Dussault told reporters.
If a preliminary inquiry is necessary, Garneau made it clear he wants it soon.
"It is an urgent priority that the preliminary inquiry be held (if one is needed)," he said. When asked by a defence lawyer about a timeline, the judge simply replied: "I can tell you that it will not take three years."
Dussault says he has doubts a preliminary inquiry can be held before the end of the year, given the wealth of evidence.
Vaillancourt quit his post in November 2012 after 23 years at the helm, in the process earning himself the nickname the "Monarch of Laval." He stepped down under a cloud of controversy but has vowed to fight the charges.
Coincidentally, the man who replaced him as mayor, Alexandre Duplessis, quit last month after stories surfaced about a run-in with an escort.