The 31-year-old joined SPorting in the closing hours of the transfer window, following an 18-month stint at Hoffenheim.
“I think that Sporting is the right club for me. I was hoping to receive a few offers, especially because I was without a contract, and I am really happy that Sporting is interested in me,” Hildebrand told the club’s official website.
“This is a great chance to continue showing what I am worth, but in another country.
“I am going to give my best to help Sporting.”