Mariners Top 20 Prospects: #5 RHP Edwin Diaz


Edwin Diaz has the potential to one day be top-3 starter in Seattle

Originally selected by the Seattle Mariners in the third round of the 2012 draft, Edwin Diaz has quickly become one of the top young hurlers in the organization. The 21-year-old right-hander was named the M’s Minor League Starting Pitcher of the Year in 2015, and represented the Mariners at last season’s Futures Game.

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The Puerto Rican born pitcher split the 2015 season between the Bakersfield Blaze and the Jackson Generals. Diaz started the year in the California League, and he was electrifying. He went 2-0 with a paltry 1.70 ERA across 7 outings. Diaz fanned 42 and issued just 9 free passes in 37 innings pitched. He also limited the opposition to 0.811 walks/hits per inning.

Diaz’s remarkable performance in Bakersfield prompted the M’s to promote him to their Class-AA affiliate in Jackson. Diaz pitched well with the Generals, but he was unable to duplicate the numbers he posted in the California League. He went 5-10 with Jackson, and registered a 4.57 ERA across 20 starts. He stuck out 103 and walked 37 through 104.1 innings.

Combined, Diaz went 7-10 with a 3.82 ERA in 27 starts last season. He led all Mariners’ minor-leaguers with 145 strikeouts in 2015, and placed 9th in all of minor-league baseball by averaging 9.2 strikeouts per 9 innings. He has excellent command of his arsenal, and he issued just 2.9 walks per 9 innings last year. Perhaps most impressive of all, Diaz limited the opposition to a dismal .237 batting average across 141.1 innings of work.

Diaz began his professional career in 2012 with the M’s affiliate in the Arizona Rookie League. He struggled during his stint in the desert, going 2-1 with a 5.21 ERA through 9 appearances. Diaz tallied 20 strikeouts and walked 17 in 19 innings.

The Mariners sent Diaz to the now defunct, Pulaski Mariners of the Appalachian League in 2013. Diaz looked much more comfortable with Pulaski, going 5-2 and posting a 1.43 ERA in 13 starts. He racked up 79 strikeouts and issued 18 free passes through 69 innings. Diaz limited the opposition to just 0.913 walks/hits per inning.

The Caguas, PR product continued to excel in 2014 as a member of the Mariners’ Class-A affiliate, the Clinton LumberKings. Diaz dominated the Midwest League, going 6-8 with a 3.34 ERA across 24 outings. He struck out 111 hitters and walked 42 in 116 innings.

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Diaz possesses a three-pitch repertoire, and all three of his offerings are considered above-average. His fastball hovers in the 92-94 mph range, but it has been known to touch 96 on the radar gun. Diaz’s slider is his out pitch, and his changeup took great strides in 2015. What makes him so difficult to hit is his funky delivery to home plate. Diaz has a low three-quarters delivery, and that gives hitters fits.

Most scouts believe Diaz’s ceiling is as a number three starting pitcher in the big leagues. He has great numbers in the minor-leagues, but some have questions about his frame. Diaz has solid height (6’3) to be a starting pitcher, but his slight build (165 lbs.) has led some to wonder if he can stay healthy over the course of 200 innings.

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The Seattle Mariners are not flush with top notch prospects right now, but Edwin Diaz is a young pitcher M’s fans should be excited about. Diaz will probably begin the 2016 season back in Jackson with the Generals, but he will likely finish the year with the Tacoma Rainiers. He has big league stuff, and Diaz should make his debut in the Emerald City at some point in 2017.