Last Updated on April 13, 2016 by

Prospect NotebookSeattle Mariners right-handed pitcher Edwin Diaz came into this season ranked No. 3 on Prospect Insider’s Mariners Top 25, and very early on scouts are thinking maybe I was a little pessimistic with that ranking.

Diaz, who just turned 22 last month, has flashed electric on his way to 11 strong innings for Double-A Jackson in 2016. He’s yielded just six hits — two extra-base hits — and one base on balls. He’s been a little shy of utterly dominant, but only a little.

“I put a lot of 6s and 7s down both times,” said one scout who’s seen each of Diaz’s outings. “He’s sinking it well and there’s some tail to it at 90-93 (mph). He showed 95 when he went four (-seamer) and at least a handful of average sliders… a few I tossed 6s on.”

Diaz throws from a three-quarters slot but has stayed on top well generating sink and inducing ground balls. The developed armside run on the two-seam sinker helps him stay out of the middle of the strike zone, which is more critical than staying down.

The club wants Diaz to throw more sinkers in the zone so he can get ahead with it, either on swings and misses, foul balls or called strikes. Through last summer, it was a pitch Diaz used mostly in two-strike counts or when he wanted to get a ground ball from a favorable count. The changeup still is a work-in-progress but at times in 2015 he displayed a fringe-average version and the more he gets batters thinking 90-95 mph fastballs the more effective even a 50-grade changeup can be. More consistent arm speed remains key.

Diaz is still a bit on the light side; he’s listed at 165 pounds, though he’s probably closer to 175-180 at 6-foot-3. He’s stronger now than even a year ago and uses his lower half better , though there’s still work to do in this area, as well as bending a little more at the waist to make sure his body supports his arm.

Diaz has yet to make what I’ll call a big-league style start; 7-plus innings, 100-110 pitches — he’s only made one 100-pitch start but lasted just 5 2/3 innings in that outing last June. The next step is the 100-110 range in back-to-back starts but his body and performance has allow the club to get there. Perhaps that takes place when Diaz is nice and loose and in warmer weather than April brings.

Stay tuned.

Was Tyler O’Neill Rushed to Double-A?
The club’s top prospect mashed last season in Advanced-A Bakersfield, particularly after starring for Team Canada in the middle of the campaign. He’s still a bit raw in some areas with the hit tool but he’s a very good athlete with tremendous desire to succeed and the Mariners saw that as worthy of an assignment to the Southern League despite being just 20 years of age.

Early in 2016 O’Neill has held his own collecting eight hits in his first 24 at-bats. He’s whiffed six times and has yet to draw a walk. He’s also pounded out just one extra-base hit. Despite the .333 batting average a few are wondering if O’Neill was rushed like several recent Mariners’ prospects appear to have been, including Mike Zunino.

The obvious answer is it’s too soon to tell, but my answer is absolutely not. O’Neill showed there’s little to nothing left for him to learn in the California League, where, by the way, the pitching talent may actually be down a notch from a year ago. Double-A was the right challenge for O’Neill, even if he has to repeat the level to start next season at age 21.

It’s also worth remembering that overall numbers, nor any specific areas of performance or the lack thereof, should dictate a club’s decision. The addition of Andy McKay as player development guru is expected to include more of an emphasis on the mental side of the game, which if inserted into the decision process, too, potentially reduces the pressure on player to put up ‘numbers.’ Instead, development, both mental and physical, should be the criterion.

For O’Neill, more specifically, strike zone judgment, overall discipline and using the middle of the field and the right-center field are some of the things he needs to improve upon this season. Of his eight hits this season, six have reached the outfield and four of them have been to either center field or to the back side, including his lone extra-base hit, a triple to right. He has at least one hit in all six games.

We’ll see where he is in June and July, but O’Neill is as safe a bet to handle the challenge, and the new M’s approach to player develop

Latest posts by Jason A. Churchill (see all)


  1. Avatar

    Thanks Jason…I figure that was the case. I prefer the half numbers as well as I think they help differentiate at different levels.

  2. Yes, Michael, 6s and 60s are the same. Some scouts don’t add the extra digit in simple form. I like the double-digit form because I use half grades like 45, 65, et al.

    Kudos for knowing the difference between what the scout said he saw and wrote down and what the overall grade of the pitch may be in the grand scheme. So many jump the gun and presume a few games is enough to change the grade and it’s sure not.

  3. Avatar

    When you are talking a scout putting down 6’s and 7’s, how does this compare to the scouting reports we see from you. By this I mean, is a 6 on a specific pitch like saying if he threw that level of pitch consistently the pitch would be comparable to a 60 grade on the scouting report? Just trying to make the correlation..thanks Jason!

  4. Yes. Always a chance a starter doesn’t finish his development (it’s very very common) and ends up a reliever, but I like Diaz’s chances to start and he has No. 3 upside.

  5. Avatar

    You still of the opinion that he could be a future no. 3?


Leave a Reply

Your email address will not be published.

This site uses Akismet to reduce spam. Learn how your comment data is processed.