The attacking midfielder, who was found guilty of failing to report attempts to arrange the outcome of two games, will now be available for the Rome derby
The 34-year-old had been initially hit with a six-month ban for failing to act over the alleged plans to arrange the outcome of the Biancocelesti's Serie A clashes with Genoa and Lecce in 2011, but the Italian Football Federation (FIGC) subsequently added a further three months to the suspension.
However, after just half an hour of deliberation on Friday, the National Sports' Court for Arbitration revoked that ruling, meaning Mauri's exile will now end on February 2.
Consequently, the attacking midfielder, who has been capped 11 times by the Azzurri, will be available for Lazio's Serie A derby with city rivals Roma seven days later.
The Calcio Scommesse betting scandal of 2011 resulted in a string of high-profile arrests, including former Italy international Giuseppe Signori, as well as a number of Italian clubs being ultimately docked points for their involvement in match-fixing.