The 27-year-old has struggled for a spot of the first-team under Lisbon's coach Jesualdo Ferreira this season after arriving at the club for a record nine million euros in 2011, reports Xinhua.
Elias becomes the first major signing under new president Eduardo Bandeira de Mello, who took charge of Brazil's biggest club last month.
The one-year agreement includes a clause allowing the player to leave in the European summer transfer window, Brazilian daily O Globo reported.
Elias, who has also had spells at Corinthians and Atletico Madrid, has won 13 caps for Brazil since making his international debut in 2010.
