The Mariners' ability to develop pitchers is well-known. We've seen them create high-leverage bullpen arms from many situations, and they elevated starters George Kirby and Logan Gilbert from strikethrowers to top-of-the-rotation hurlers. However, lately, we've seen them invest in some youngsters on the offensive side, like the speedy Jonatan Clase, who comes in at #8 in our prospect rankings
Clase came up as a slap-hitting outfielder who used his speed to leg out hits, showcasing these skills in a spectacular 2019 debut season (.300/.434/.878). He spent that season in the Dominican Summer League, leading the circuit in steals with 31. The 21-year-old is still most likely the fastest runner in Seattle's system, with fellow top prospects Felnin Celesten and Ryan Bliss hot on his heels.
He'd spend the next few seasons working on his conditioning, which has paid big dividends in the power department, as Clase has launched 32 homers over the past two years. 2023 was a breakout campaign for the Dominican-born outfielder, as he was one of only three minor leaguers to hit 20 homers (20) and steal 50 bases (79). However, with the power focus has come a significant amount of strikeouts (165 this season). Luckily, Clase balanced the swing and miss with some keen strike zone judgment, accumulating 82 walks across two Mariners' farm system levels.
Clase is still honing his routes in centerfield, which he makes up for with the 70-grade speed. Once he locks down the defensive side of the game, the sky is the limit. We'll see him start the 2024 season again in Arkansas as he finds the balance between contact and power to cut down on the strikeouts. There is an off chance of seeing the unique skills of Clase roaming the outfielder grass in T-Mobile as a late season callup.