Baseball America, 2018: “Evaluators largely see Yamamoto as a future reliever, at best, because of his slight frame and lack of a plus pitch.”
Baseball America, 2019: “His late-breaking, downer curveball is his best secondary offering, flashing plus at times...He has the potential of a mid-rotation starter.”
What a difference a year makes for Marlins right-hander Jordan Yamamoto. Despite an age-22 season that was interrupted twice by stints on the disabled list, the most unheralded piece of the Christian Yelich trade package forced his way onto the 40-man roster and into consideration as a long-term rotation candidate.
How did he get here? Traded from Brewers to Marlins on January 25, 2018
2018 MiLB Stats: 1.83 ERA, 2.17 FIP, 0.83 WHIP, 85 K in 68.2 IP
2019 ZiPS Projection: 4.41 ERA, 4.33 FIP, 1.37 WHIP, 74 K in 81.2 IP
Entering this season ranked by BA as the No. 18 Marlins prospect, Yamamoto is unlike the prototypical power arms that the front office has focused on in recent years. His fastball sits in the low 90s on a good day, and first time through a lineup, his velocity is actually a few ticks lower than that.
But it works. He didn’t allow more than two earned runs in any of his 13 regular season starts in 2018. He set a High-A Jupiter club record with 13 strikeouts against the Florida Fire Frogs on June 20. In his final appearance with Double-A Jacksonville, Yamamoto worked six hitless innings.
Undersized for a potential major league starter at six-foot-nothing, the proud Hawaiian fills up the strike zone with plus control. The only hiccup came during the Arizona Fall League—17 walks in 30 total innings when including the AFL Championship Game. There were outings in the desert where he struggled to repeat his delivery, but that may be attributed to simple fatigue from the extended campaign.
The curveball has emerged as Yamamoto’s top put-away pitch. He showcased it in the AFL...
And again during his relief appearance against the Mets last month:
However, given the surplus of healthy, experienced arms, Yamamoto was never seriously in the mix for the Marlins Opening Day roster. He worked two Grapefruit League games—2.25 ERA in 4.0 IP—before being optioned to Triple-A New Orleans as part of the first round of cuts on March 8.
He still gets to wear that “cool” blue on the backfields at the Roger Dean Chevrolet Stadium complex.
Yamamoto was bumped up to New Orleans on paper, though it remains to be seen whether he will actually report there in April. There’s still time for the Marlins to coordinate their affiliate rosters. Promoting a starter to Triple-A after only three starts at the Double-A level would be strangely aggressive in a rebuilding year.
Newly acquired top prospect Sixto Sánchez is expected to slide into the Jacksonville rotation this summer, but the initial plan, according to vice president of player development and scouting Gary Denbo, is to observe him at extended spring training (h/t Joe Frisaro, MLB.com). Should Yamamoto continue to succeed in the Southern League, you might see him make the move in May or June, around the time that Sánchez is cleared to fill his shoes. In the event of significant injuries above him on the depth chart, there is the potential for a late-season call-up to Miami.
Barring a surprising velocity boost, the concern for Yamamoto moving forward is how much damage elite batters will do when he misses over the heart of the plate. Does he have the deception and clever sequencing to avoid a home run barrage?