Sunderland manager Paolo Di Canio bolstered his squad ahead of the new Premier League season by completing the signings of three players on Monday.
Defenders Modibo Diakite and Valentin Roberge arrived on free transfers after their contracts at Italian side Lazio and Portuguese team Maritimo, respectively, expired.
Midfielder Adilson Tavares Varela - who is better known as Cabral - also signed a three-year deal after moving to the northeast of England from FC Basel, where he won the Swiss league four times. He is from Cape Verde but holds Swiss citizenship.
Sunderland narrowly avoided relegation from the Premier League last season, finishing one place above the bottom three.