Marin signed a five-year contract with the London club last summer following a move from Werder Bremen, however a hamstring injury sustained before the season started restricted him to just 15 appearances in all competitions.
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A club statement read: "Chelsea Football Club and Sevilla Futbol Club have reached an agreement for the season-long loan of Marko Marin, subject to the completion of legal documentation and a medical."
The German told Goal in May that he was unsure about moving away from the club on loan this summer but was willing to let Rafa Benitez' successor determine his future.
And Jose Mourinho's return to Stamford Bridge has seen Marin depart the club on loan, having fallen further down the pecking order following the arrival of compatriot Andre Schurrle from Bayer Leverkusen.