The decision confirmed Monday was anticipated, with Chen due $52 million over the final three years of the $80 million, five-year deal he signed in early 2016.
Chen's availability in 2018 is in doubt because of a balky left elbow that limited him to nine games this season and 22 in 2016. He was sidelined from May 1 to Sept. 4 this year and allowed one run in six innings in four late-season relief stints.
Chen was a durable starter with Baltimore and has a career record of 53-38 in six seasons, but is only 7-6 with the Marlins.
His deal calls for $10 million next year, $20 million in 2019 and $22 million in 2020, with $30 million of the total deferred.