Barcelona have confirmed they're looking to take legal action against Santos as they feel the Brazilian club did not comply with their preferential option to sign striker Gabriel Barbosa.
Gabigol, as Barbosa is better known, signed for Inter Milan for a fee in the region of €25 million on Aug. 30.
Santos made Barca aware of the Italian side's bid on Aug. 29, allowing them just one day to decide if they wanted to act on their option to match the bid.
However, an agreement signed between the two sides in 2013 stipulates that Barca should have been permitted three days to evaluate whether they wanted to move for the 20-year-old.
"The club are in a legal process," the Blaugrana's director of professional sports Albert Soler said on Thursday.
"We had a preferential option on the player which wasn't complied with by Santos. We're studying all the legal possibilities to take the case forward, but it's a legal matter, not a sporting one."
Soler made his comments during the presentation of Paco Alcacer, who joined Barcelona from Valencia at the end of the transfer window, filling the fourth forward void Gabigol had previously been linked with.
Alcacer supplements an attack featuring Lionel Messi, Luis Suarez and Neymar, but despite the competition for places, the Spain international had no doubts about making the switch.
"It's a step forward in my career as a footballer," he said. "The manager will now decide what role I have. It's a long season and anything can happen -- everyone is here to add what they can to the team.
"Sergi Roberto is one example to follow. He started as a central midfielder and has ended up playing a number of positions -- right-back, right wing...
"So I will play where the manager decides, no problem. I'm keen to grow as a player alongside the best players in the world. It's a privilege."
�� Look back at the best pics of Paco Alcácer's presentation https://t.co/0x2o7JAI3F pic.twitter.com/d7burSu1I6
- FC Barcelona (@FCBarcelona) September 8, 2016
Since the transfer a campaign has been launched by some Valencia fans criticising for Alcacer giving up first-team football at Mestalla to become back-up for Messi, Suarez and Neymar.
"People are free to express themselves as they want and I have to respect that," the forward said about that campaign. "I wish Valencia the best and hope they return to the top level. I'm only thinking about the future now."