The former Brazil international has returned to Vila Belmiro after being deemed surplus to requirements at San Siro by new coach Pippo Inzaghi.
The former Brazil international made 23 appearances in Serie A last season but was deemed surplus to requirements by new coach Pippo Inzaghi.
Consequently, after protracted negotiations over a return to Vila Belmiro, Robinho has now been cleared to rejoin the club at which he started his career.
"Santos is my home," he told the Brazil club's official website. "It's a place in which I feel really good. I hope to repay all of the fans' affection on the field."
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Robinho joined Milan from Manchester City on a four-year deal in the summer of 2010 for a reported 18 million-euro transfer fee.
Despite an impressive debut season at San Siro in which he scored 14 Serie A goals, he struggled for both form and fitness in the coming seasons and it came as a surprise when he signed a contract extension last summer binding him to the Rossoneri until 2016.
However, Robinho has been linked with a return to Santos all summer long and the 30-year-old attacker has finally put pen to paper on a one-year loan agreement with the Brazilian outfit.