Abreu was optioned to Double-A Trenton on Sunday.
Abreu missed the start of last season after undergoing an appendectomy and posted a 4.16 ERA, 1.33 WHIP and 65:29 K:BB in 13 starts at High-A Tampa. The 23-year-old finished the year with one start at Trenton and returns to the Thunder to begin the 2019 season.