The defensive midfield player was released by Hertha Berlin at the end of last season and had been without a club since.
The 33-year-old becomes the third Brazilian in compatriot Luiz Felipe Scolari's squad, after defenders Alex and Juliano Belletti.
Mineiro has won 24 caps for Brazil and was a member of the 2006 World Cup squad, as well as appearing against England at Wembley in 2007.
"So this week he will not play but maybe after 15 days to two weeks, he is ready to play normal games. He needs to play some games in the reserve team, and for me it is very good because I have one more player in this position. If not I have to put in Belletti or [Paulo] Ferreira, or [Michael] Ballack, and they are not for this position.
"I say to fans of Chelsea, if they remember [Claude] Makelele, Mineiro is the same. Good positionally, a very good marker. He is a man that works for the other players and he is also a good man outside of the pitch."
Mineiro spent 18 months with Berlin, making 36 Bundesliga appearances and scoring twice, after having moved to Europe from Brazil, where he had spells with Ponte Preta, Sao Paulo and Sao Caetano.