From his scouting report: Needs to improve pitch recognition, especially against breaking balls. Some questions about how his contact skills will translate against more advanced pitching.
It's not a surprise that he's now struggling with a split.
GRE 23: 37.5 k% vs LHP, 20.0 k% vs RHP
SAL 22: 34.8 k% vs LHP, 23.9 k% vs RHP