"The protest is cancelled," read a statement.
Tuesday's seven-hour meeting at the football federation headquarters in Rome was followed by more lengthy talks on Thursday and an agreement was finally found.
The union was in dispute with Serie A over parts of a new collective contract which guarantees basic players' rights, namely club plans to force unwanted footballers to train away from the first team or accept a transfer.
Thursday's deal means all players with first-team contracts must be allowed to train with the main squad while rules to avoid discrimination have been agreed for unwanted footballers who are put up for sale.
"The union thanks the players who showed... a high sense of responsibility to defend their professional dignity and the fundamental rights of all workers," union president Sergio Campana said.
Both players are awaiting their full arbitration hearings with Italy forward Cassano's due to take place on Friday, although a decision on whether Samp's action is lawful and whether he is a now free agent may take some time.
A first strike was called by the union in September but was postponed to allow more talks. However, as negotiations dragged on without a deal, the union threatened new industrial action for this weekend's matches.
