Prospect Breakout: Can Isan Diaz Finally Emerge In 2019?


Isan Diaz was one of the key pieces to the trade that sent Christian Yelich to Milwaukee, but his first season as part of the Miami system was rather unimpressive.  Splitting time between Double and Triple-A, Diaz posted the following uninspiring numbers:

  • Double-A (294 AB) – .245, 10 HR, 42 RBI, 44 R, 10 SB
  • Triple-A (137 AB) – .204, 3 HR, 14 RBI, 19 R, 4 SB

Obviously a 13 HR/14 SB second baseman is going to catch our attention, especially in 431 AB, as it would lead to a 15/15 projection (though there are questions about his speed, making 20/10 a more believable expectation).  The question is going to be whether or not he can make consistent contact, because if not the average is going to continue to be an issue.  Just look at the strikeout rate // SwStr% from ’18:

  • Double-A – 26.7% // 9.1%
  • Triple-A – 29.0% // 11.6%

There was a regression upon his promotion to Triple-A, albeit in a smaller sample size.  He’s also consistently proven capable of drawing a walk, with an overall 13.3% walk rate last season (after a 13.5% mark in ’17).  A strong approach and the ability to make contact at Double-A gives reason for optimism, because all he needs to do is to hit .260ish with his power and speed.

As noted by in their recent scouting report:

He can get aggressive at times, but his hand-eye coordination and patience should have translated into better than a .254 career average in his first five pro seasons. He did make some adjustments last year to reduce the uppercut in his left-handed stroke, but they didn’t produce noticeably better results.

Speaking of his power, that appears to be his best skill.  He added 23 doubles and 5 triples last season, with 20+ HR annually a fair expectation. 

The questions all come from his ability to make contact, and it will be interesting to see if the adjustments he made begin to truly pay dividends.  We saw it in the SwStr% at Double-A, and if that starts to translate to fewer strikeouts (as we’d expect) it won’t be long before he starts getting talked up significantly more.

Currently flying under-the-radar, the Marlins need a second baseman of the future and the future could come in 2019 (especially with Diaz turning 23-years old in May).  Keep a close eye to his start, as he could be promoted quickly (he is on the 40-man roster) and is capable of making an impact.

Sources –,, Fangraphs

Make sure to check out all of our 2019 Top 10 Prospect Lists:

AL EastAL CentralAL West
Baltimore OriolesChicago White SoxHouston Astros
Boston Red SoxCleveland IndiansLos Angeles Angels
New York YankeesDetroit TigersOakland A's
Tampa Bay RaysKansas City RoyalsSeattle Mariners
Toronto Blue JaysMinnesota TwinsTexas Rangers
NL EastNL CentralNL West
Atlanta BravesChicago CubsArizona Diamondbacks
Miami MarlinsCincinnati RedsColorado Rockies
New York MetsMilwaukee BrewersLos Angeles Dodgers
Philadelphia PhilliesPittsburgh PiratesSan Diego Padres
Washington NationalsSt. Louis CardinalsSan Francisco Giants


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