Ryu is working on adding a slider to his pitch mix, Bill Plunkett of The Orange County Register reports.
Ryu threw a slider early on in his career, though he phased the pitch out over the past two seasons in favor of a cutter. The southpaw is planning to reintroduce the pitch in 2019, adding it to a repertoire that already features a fastball, cutter, curveball and changeup. Ryu has yet to test the pitch out this spring, though that hasn't stopped him from impressing early on -- he fired another two scoreless innings in Friday's game against the Padres, allowing two hits while striking out two.