Colourful Cassano, constantly in trouble in the past for various antics before appearing to have matured, has been suspended by Samp since verbally abusing club owner Riccardo Garrone in late October and refusing to attend a dinner.
A first hearing on Friday failed to resolve the dispute, with Samp asking for his contract to be voided while Cassano's lawyers argued that the former Real Madrid man has been unfairly treated given he has apologised and wants to stay.
"Conciliation has been unsuccessful so a decision has to be made in arbitration. There will be another hearing on Monday after which I will announce the verdict," arbitration chairman Paolo Giuggioli told reporters
Giuggioli heard from witnesses including Samp players who saw the foul-mouthed outburst from 28-year-old Cassano, who missed Italy's friendly draw against Romaina last month because he was not playing for his club.
Media have questioned why Garrone is pursuing the action when he could sell his top player for a decent fee in January rather than allowing him to walk away for free immediately if Samp are successful.
The case is the opposite of last season's Goran Pandev affair where the Macedonia striker took Lazio to arbitration having been dropped for asking for a transfer and won the right to join Inter Milan on a free.
Italy's World Cup goalkeeper Federico Marchetti, who has not played a competitive game since the Azzurri's exit in South Africa in June, is taking Cagliari to arbitration after being dropped for the same reasons as Pandev.
His second hearing is due before the end of the year.
The propensity for Serie A club presidents to drop players because of disagreements was a major reason why top-flight players were planning to strike for this weekend's matches before a deal with the league on Thursday averted the action.
Cassano has been linked in the media with Juventus and several other Serie A clubs but Inter president Massimo Moratti has said speculation the champions were interested was "fantasy football" despite their lack of forward options.
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