Castano is part of the Marlins' 60-man player pool, Craig Mish of SportsGrid.com reports.

He is not on the 40-man roster and has never reached the majors. The 25-year-old lefty logged a 3.35 ERA, 1.14 WHIP and 73:16 K:BB in 86 innings, primarily as a starter, at Double-A last season.