Braga are to report Atletico Madrid to FIFA over a €1.5 million loan fee they are still owed for attacker Pizzi's spell at the Vicente Calderon last season, according to reports.
Portuguese sports newspaper A Bola said Atletico had been due to pay the full amount by June, but Braga had yet to receive any money from the financially-troubled club.
Pizzi, 23, made 15 appearances for Atletico last season, scoring once. Atletico agreed to continue the loan for another season before themselves loaning him to fellow La Liga side Deportivo la Coruna in July.
In October, it was reported that Atletico had decided to take up an option to buy the player for €13.5 million at the end of the season, with the payments to be staggered over four years.
A Bola has reported that the first €3 million of that fee is due to be paid to Braga in January.
Pizzi has impressed at Depor so far this season, playing regularly and scoring four goals including a fine free-kick against La Liga leaders Barcelona.
He made his full debut for Portugal earlier this month, scoring a penalty in a 2-2 friendly draw in Gabon.
"It [€13.5 million] is a very big amount, above all at the moment with the financial crisis," he said when Atletico's purchase was announced in October.
"This is a vote of confidence in me, and I will try to make things go well. I am not a better or worse player because Atletico paid €13.5 million for me. I must work every day to show it."
The Braganza-born attacker's tangled career path has been the subject of much controversy and speculation in Spain.
In July, Marca reported that his rights had been bought from Braga by Quality Sports Investment, a third-party ownership investment fund linked to Portuguese agent Jorge Mendes and former Chelsea and Manchester United director Peter Kenyon.
Atletico have repeatedly denied reports that a similar arrangement was behind their heavily indebted club's €45 million purchase of striker Radamel Falcao in 2011.
Falcao, who continues to be linked with a €60 million move to Chelsea, is not expected to feature in Atletico's Europa League Group game at home to Hapoel Tel Aviv on Thursday.
Europa League and European Supercup winners Atletico were one of the 23 clubs named by UEFA in September from whom prize money is being withheld while they get their finances in order.