Emerson has left Milan after having his contract terminated with immediate effect.
The Brazilian midfielder asked for the decision to be taken for family reasons and the club have granted his request.
Emerson moved to the San Siro from Real Madrid in 2007 but injuries have restricted his appearances over the past two years.
The 33-year-old had previously enjoyed spells with Juventus, Roma and Bayer Leverkusen, after starting his career with Brazilian club Gremio.
Portsmouth were also linked with a move for Emerson in the January transfer window.