Reports emerged on Thursday suggesting the Brazilian is considering a loan switch to the Portuguese club in a bid to revitalise his European career.
His representative, Wagner Ribeiro, has confirmed discussions with Sporting are underway.
"We're talking with president Bruno de Carvalho," he told Record. "We'll see if we can close the deal."
The 20-year-old, known as Gabigol, has struggled to settle in Italy since his reported €29.5 million move from Santos in 2016.
"It will be another year in Europe for me and I believe that I will be more prepared, more mature in order to play at my best," he said last month.
"I hope this evolution can be shown on and off the pitch. I believe that. Even during the break, I made a point of staying in good physical and mental shape.
"I did physical work during this period to get back to Europe well. Now I will continue this and achieve my best physical and technical form in the season that will come."