Alves has been a free agent since leaving Brazilian outfit Sao Paulo last month over a dispute about images rights.
However, the 38-year-old will only be able to play with the Catalan giants from 1 January 2022 as he became a free agent after the off-season window closed.
Statement:
Didier Drogba (Chelsea)
Nemanja Matic (Chelsea)
Jermain Defoe (Tottenham Hotspur)
Thierry Henry (Arsenal)
Wayne Rooney (Everton)
Robbie Fowler (Liverpool)
Juninho Paulista (Middlesbrough)
Sol Campbell (Arsenal)
Romelu Lukaku (Chelsea)
Gareth Bale (Tottenham Hotspur)
Paul Pogba (Manchester United)
Cristiano Ronaldo (Manchester United)