Chisholm, a 21-year-old shortstop in Double-A, has had a down year, holding a .732 OPS for the year. MLB Pipeline make him the 59th-best prospect in baseball. He’s a special athlete, and one of the toolsiest players in the minors with a great arm and superb hand-eye coordination.
A left-handed hitter, Chisholm has the potential to become a true five-tool superstar. He’s got speed, can hit for power and has quick hands. Miami have gone for the upside and the tools despite Chisholm’s struggles at the plate this season.
The Diamondbacks get a young pitcher in Gallen, who is currently Miami’s fifth-best prospect per MLB Pipeline. Gallen has made seven Major League starts this season, good for a 3.58 FIP, 2.72 ERA with 10.7 strikeouts per nine. He’d previously dominated in Triple-A, and will slot straight into Arizona’s rotation.
Having arrived in the Marcell Ozuna trade back in late 2017, Gallen’s stock has risen quickly. His stuff has improved. Gallen’s cutter is his best pitch, which he can throw wherever he wants for strikes, but his change and curveball are more than useful too, helping him to keep pitchers off balance.
The Diamondbacks, who have decided against a teardown rebuild, have prioritised certainty over Chisholm’s upside. This was a shock trade from both parties, but it fits with their relative approaches. The Marlins like players with tools, and they’ve got plenty of young pitching. The Diamondbacks are looking to remain competitive while reconstructing their roster – adding a Major League starter with several seasons of club control suits that philosophy.