Hearing an appeal from Matuzalem, the court overturned a ruling by FIFA and CAS that the 31-year-old could be banned from playing if he missed compensation payments to former club Shakhtar Donetsk.
The court described that ruling as "fundamentally unlawful".
Matuzalem and Real Zaragoza were ordered by CAS in 2009 to pay Shakhtar Donetsk almost 12 million euros for breach of contract, following the player's move from Shakhtar to Zaragoza in 2007.
In August 2010, FIFA ruled that Shakhtar could request a ban for Matuzalem if he failed to pay on time and this was confirmed by CAS in June last year.
"The CAS decision has been annulled because it is incompatible with the public order," the Swiss court said in a statement.
"An unlimited ban from exercising his profession, such as the one with which the player was threatened, constitutes a manifest and serious attack on the rights of the individual," it said.
"If he did not make the payments imposed on him, he would be at the mercy of his former employer to such an extent that the base of his financial existence would be put in danger."
Matuzalem and Zaragoza still had to pay off the sum owed to the Ukrainian club plus interest of five percent a year, the court's judgement said.
Matuzalem was raised at Brazilian club Vitoria and represented his country at under-17 and under-20 levels.
He has also played for Swiss side Bellinzona and Italian clubs Parma, Napoli, Piacenza and Brescia.
Zaragoza are currently in financial administration and bottom of La Liga.
