The 18-year-old winger's signature is one of the most coveted in Europe after some wonderful performances for Portugal at the recent FIFA Under-20 World Cup.
A number of clubs have been credited with an interest in Bruma, and Chelsea and Galatasaray are reported to have already submitted offers.
While it is understood that those bids were rejected, the situation has been further complicated by a dispute over the player's contract with Sporting.
Bruma's lawyer, Bebiano Gomes, says the deal expired at the end of last month, but the club have insisted there was a clause that triggered an automatic renewal.
Gomes is convinced that Bruma's ties with the club have now been severed, which would make him a free agent, telling TVI: "Now Bruma heads totally out of Sporting. If the case goes through the courts, no problem."
Bruma admits the situation has been far from ideal but he is now looking to the future and is likely to have plenty of options to consider, with Porto understood to be back in the race for his signature.
"I deeply regret the outcome of this matter. I did everything to stay at Sporting and I made it clear to my representatives to try to reach an agreement. But after all this time, Sporting did little for me to renew," he told A Bola.
"I want to avoid any sort of controversy with Sporting and especially with the fans. I am a professional and I will continue my career."
There has been uncertainty for some time over whether Bruma would stay at Sporting and his future was plunged into doubt earlier this week when his agent was quoted as claiming that there had been a kidnapping attempt on the player.