Born in Alegrete, Rio Grande do Sul, Sidnei started playing professionally with Sport Club Internacional, being part of the side that conquered the 2007 edition of the Recopa Sudamericana.

[5] He played only five league matches the following campaign – ten competitive appearances – as the club won the national championship after a five-year wait.

After spending the first half of 2010–11 on the bench, Sidnei was propelled to the starting XI after David Luiz moved to Chelsea in the winter transfer window.

[6] On 21 February 2011, he was sent off in a league game at Sporting but his team still managed to win it 2–0[7] and, later the following month, he renewed his contract for a further three seasons until 2016;[8] however, due to poor performances, he lost his starting place to Jardel.

[26] The following 25 March he terminated his contract and joined Goiás Esporte Clube,[27] but also left the latter on 5 July having totalled just seven appearances for both sides.