Lewin Díaz needs to show Marlins he can hit MLB pitching

The Marlins do not believe in Lewin Díaz and this is perhaps his final chance to prove them wrong. How did we arrive at this fork in the road?

In July 2019, they acquired Díaz from the Twins to address a need. No MLB team was getting less power production at first base than the Marlins, where they had been rotating Neil Walker, Martín Prado and a not-yet-established Garrett Cooper. In the upper minors, they didn’t have anybody who projected to be a long-term answer there. So they packaged surplus pitching—pending free agent Sergio Romo and prospect Chris Vallimont—for Díaz, who had taken significant strides forward as a slugger and fielder in his age-22 season.

Playing 150 total games in 2019 (MiLB affiliates and Dominican winter ball combined), Díaz homered 30 times while maintaining above-average contact rates and facing mostly older competition. The Marlins didn’t hesitate to select him to their 40-man roster, protecting him from the Rule 5 Draft. As baseball was getting ready to resume following its 2020 COVID hiatus, Miami’s front office was still enamored with him, according to Craig Mish of SportsGrid:

Since then, Díaz has continued to look the part of an impact player when suiting up for Triple-A Jacksonville (.250/.325/.504, 39 HR in 156 G). Unfortunately, his success isn’t translating to the majors. By weighted runs created plus, Díaz has been merely half the hitter in The Show (59 wRC+) that he was at the highest MiLB level (116 wRC+).

Díaz got a cup of coffee in the majors in 2020, then a more substantial opportunity in late 2021 after Jesús Aguilar suffered a knee injury. The Marlins’ perception of him clearly shifted during that period—to the surprise of myself and many others, they spent nearly $10 million to retain both Cooper and Aguilar entering the 2022 campaign, blocking Díaz’s path to the active roster. In the process, they also used up his final minor league option year.

Díaz’s defense at first base has been as superb as advertised. He can scoop, throw, stretch and react at a Gold Glove-caliber level. In less than half a season of regular season action with the Marlins, he has accumulated 13 defensive runs saved and six outs above average. He is far more valuable than Miami’s other first basemen in that facet of the game.

The Marlins holding back Díaz as much as they have speaks entirely to their concerns about his bat.

Let’s throw out 2020. It was Díaz’s worst period of MLB production, and understandably so: the Marlins recalled him out of necessity in the midst of a COVID outbreak. That still leaves him with a .190/.246/.374 slash line (68 wRC+).

Díaz is making a lot of poor swing decisions, chasing 42.7% of pitches outside the zone since 2021, per FanGraphs. The only MLB qualifiers with higher rates than that over the same span are Salvador Pérez and Javier Báez. They are outliers.

Although Díaz is coordinated enough to make a lot of contact when he chases, it just isn’t worth it. All but one of his extra-base hits as a major leaguer have come off pitches in the strike zone, according to Baseball Savant.

Díaz was an everyday player for the Fish in the closing weeks of 2021, which meant facing plenty of left-handed pitchers. But after going walk-less with 14 strikeouts in those 39 plate appearances, they have carefully platooned him in 2022.

Even if Díaz gets himself in the correct mindset to stay in the zone, the question is whether he can catch up to MLB velocity. Opponents are throwing him fastballs 61.0% of the time this season (league average is 55.5%). He had been struggling with that until Sunday, when he stroked a home run and a double against Dodgers rookie Ryan Pepiot. Encouraging!

I don’t see a scenario where the Marlins can enter 2023 with Lewin Díaz as their unimpeachable “first baseman of the future.” The bar has been lowered. During this final quarter of the season, they are hoping that he can tap into his plus power tool with some regularity when put into advantageous matchups, doing just enough to justify a roster spot on a competitive team.

If that doesn’t happen? The Marlins could find themselves back where they were a few years ago, and Díaz could find himself on the waiver wire come spring training.