After clearing waivers, the Marlins on Friday outrighted Mattison to Triple-A New Orleans. The 27-year-old also will be at Spring Training as a non-roster invite.
Mattison, a left-handed-hitting outfielder, was designated for assignment on Wednesday to clear roster room for reliever Sam Dyson, who was claimed off waivers from the Blue Jays.
Mattison batted .241 with 13 home runs, 41 RBIs and 26 stolen bases for New Orleans in 2012. He appeared in three games for the Marlins.
The Marlins right now have 72 players preparing to participate in Spring Training.