Late on Friday, a panel of nine judges said further investigation was necessary before it could make a final decision on the midfielder's appeal, a statement read.
The ban remains intact while the court probe continues, and no deadline for a verdict was set. However, Rome daily il Messaggero said the investigation, which is likely to include new testimony from Mauri, would probably begin next week.
That means the left-footed 33-year-old, a pivotal player for Lazio, will sit out the first game of Italy's 2013-14 season, which pits the winner of last year's Serie A, Juventus, against Coppa Italia champion Lazio.
The regular Serie A season kicks off a week later on August 24-25.
Mauri was handed the six-month ban in July when the court ruled he had knowledge that May 2011 matches against Genoa and Lecce had been manipulated, but kept silent. The Lazio team was also handed a 40,000-euro fine.
"Mauri was convicted only for a failure to report (match-fixing), but we don't exactly what he did, because it is not clear when and how he could have known whatever was done to alter the results," Lazio lawyer Gian Michele Gentile told SkyTG24.
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