He started his first game for PSV in January 2009. Soon after, the 21-year-old former Brazilian U-20 national squad goalkeeper moved to Sparta Rotterdam until the end of the season. In the 2011–12 season he played at the second team. On 28 September 2011 his contract was terminated by mutual consent and Ramos returned to Brazil.
Corinthians
In the end of 2011, after terminating his contract with PSV Eindhoven, Cássio signed with Corinthians. On 27 April 2012, he was made Corinthians' first-choice goalkeeper, replacing Júlio César, the former number one goalkeeper at the club. He made his debut in the Libertadores 2012 on 2 May 2012, in a game against Emelec in the round-of-16. The result was a goalless draw and Cássio was elected Man of the Match following a great display. He went on to make 7 more appearances for Corinthians in the competition, helping the team become champions, including a miraculous save against Vasco da Gama in the second-leg of the quarter-finals. On 16 December 2012, Cássio helped Corinthians beat Chelsea by the score of 1–0 in the FIFA Club World Cup. He was later rewarded the golden ball for the tournament due to his brilliant performances during the competition.
International career
He has been capped at Under-20 level for Brazil and played for the U-20 World Cup in Canada. The first call came in 2007 by Dunga for two friendly matches against Chile and Ghana. He was 19 years old and was called up due to Helton's injury; and also because Dunga was calling some players under the Olympic age to prepare for the 2008 Summer Olympics. Eventually he did make it to the preliminary squad for the Beijing Games, but lost out a place in the final list to Renan and Diego Alves. In August 2012, Cássio was called up by Mano Menezes for two friendlies against South Africa and China. He was called up by Brazil coach Dunga in 2015 for two games of 2018 FIFA World Cup qualification and was called up again three times by Tite in the second semester of 2017 for four consecutive games of the 2018 FIFA World Cup qualification and two friendlies. He was given his first cap with the top eleven team on 10 November 2017, coming in as a substitute for Alisson for the second half of the friendly against Japan. His participation was minimal due to Japan's limited attempts on goal, but he ended up conceding two goals from Makino and Sugimoto, though the latter's was nullified. In May 2018 he was named in Tite’s final 23 man squad for the 2018 World Cup in Russia. He also was part of the 2019 Copa América's winning squad.
