The 22-year-old said he was looking forward to a new challenge in Portugal.
"I am delighted to start training and playing here," he told Sporting's website.
"Sporting is one of the big Portuguese clubs and is recognised for having top players. The club is always looking to win titles. I will give everything for Sporting."
He made 44 appearances for the club but was sent out on loan to Galatasaray last season.