Updated: by

It’s the 11th annual Prospect Insider Seattle Mariners prospect rankings. A few things you should know before continuing:

Ceiling/potential value is only part of the equation. Probability, among other things, also is a significant factor.

The player’s likely future role can dictate his value as much as his chances to get to the majors or his upside.

I value upside more than simple depth, and if the ‘depth’ in question carries more risk than anything else, it’s not really depth.

I greatly value the reliable information I can gather on a player’s offseason training habits and how he handles himself between games during the season.

Simply put, the same bat at a premium position is more valuable. The position tree: catcher, shortstop, second base, center field, third base, right field, left field, first base.

Pitcher prospects carrying the high probability of late-inning relief work are not typically as valuable as potential starters, even if their chances of getting to the majors are greater, and/or they are closer to the big leagues. A potential setup man or closer with a 2016 ETA, however, may very well be more valuable than a high-risk, medium reward starter who is four-plus years away.

The potential for superstardom, all-stardom and average everyday contributions far outweighs a high probability fringe regular. The whole point of a farm system is to avoid free agency as much as possible to maintain great financial flexibility to supplement a good club and make them World Series contenders.

Fringe-regular talents are a dime a dozen. The lone possible exceptions are catchers, in which a case-by-case basis will be utilized. This is why higher-risk talents will rank higher for me than higher-probability prospects with a fringe-MLB ceiling.

Below are the Top 25 prospects in the Seattle Mariners organization.

Stay tuned for scouting reports throughout the spring and summer.

Kyle Lewis OF A+
Tyler O’Neill OF AAA
Mitch Haniger OF MLB
Max Povse RHP AA
Brayan Hernandez OF A-
Chris Torres SS A-
Thyago Vieira RHP AA
Dan Vogelbach DH AAA
Nick Neidert RHP A+
Andrew Moore RHP AAA
Joe Rizzo 3B A
Dan Altavilla RHP MLB
Ben Gamel OF AAA/MLB
D.J. Peterson 1B AAA
Greifer Andrade 2B/SS A-
Rob Whalen RHP AAA
Pablo Lopez RHP A+/AA
Tony Zych RHP MLB
Luis Liberato OF A+
Boog Powell OF AAA
Braden Bishop OF A+/AA
James Pazos LHP AAA
Tyler Marlette C AA
Chase De Jong RHP AAA
Emilio Pagan RHP AAA

The Seattle Mariners traded away several of their better prospects over the winter, including Zack Littel, Drew Jackson, Luiz Gohara, Carlos Vargas and Alex Jackson. In all, 11 of my Top 25 from the end of last year are no longer in the organization and another no longer qualifies — Edwin Diaz.

It’s truly one of the worst farm systems in baseball but with a lot of intrigue, a top 50 All-MLB prospect in Lewis, a top 100 prospect in O’Neill and a help-now prospect in Haniger.

Lewis has star potential, assuming he returns to 100 percent after the knee injury. O’Neill still is more of a slugger, but puts in so much time trying to get better, it may just be a matter of time before he answers some question about the hit tool.

I’m not quite as high as Neidert as some, but I do like him more than others, despite a limited upside.

I’m also not as high on Moore as anyone else, it seems. He only ranks No. 10 because the system is weak. I can’t find any talent evaluators who’d bet lunch he’s a reliable big-league starting pitcher.

“Reliever” and “swing arm” is the most common opinion I’ve seen and it’s difficult to argue. No plus pitch and despite a lot of 45-50 grades there’s no projection in his 5-foot-11 frame.

He’s close to the big leagues and could help in 2017, but expecting anything beyond a useful arm is probably too much.

Here are some other names on which to keep an eye:

Luis Rengifo, 2B
Switch hitter, above average runner, position is unclear; second-base bat, may lack actions to play their long term. Just turned 20.

Dillon Overton, LHP
Legit depth for 40-man roster. Limited upside due to fringy velocity but average curveball-changeup-command combo.

Geoandry Montilla, C
20, needs to get stronger to stick behind the plate. Good athlete, shows some game pop to pull side. Good plate skills, average arm.

Nick Wells, LHP
Fastball-curveball-changeup lefty. Needs to add strength, refine mechanics. Has touched 93.

Guillermo Heredia, OF
26, can help outfield depth on 25-man as plus runner, above-average glove. Limited offensively.

Brandon Miller, RHP
Plus control, average command and still some projection left. Started 13 games in ’16, but has a chance as a reliever to move quickly.

Tim Viehoff, LHP
Fastball-slider-changeup lefty up to 92 mph as a starter, 94 in relief and there may be more in there for the 6-foot-4, 200-pound Southern New Hampshire product.

Bryson Brigman, 2B
At times listed as a shortstop; Not much chance to stay there, in my opinion. Heady player, above-average speed, solid defender at 2B but no power at all with swing-and-miss of 15-homer bat.

Eric Filia, OF
Good hitter with a plan, short swing and good hand-eye. Solid corner outfield glove, average runner. Needs to show mettle versus better pitching. He’s 24 with no experience above short-season A ball.

Kyle Wilcox, RHP
Throws hard — up to 98 — slider flashes above average. Has a changeup from his days as a starter. Control and command well below average.

Lukas Schiraldi, RHP
Schiraldi, 23, lacks arm speed to maximize strength for velocity. Typically sits 87-90 from 3/4 slot. In a relief role with more effort may add a few miles per hour and sharpen the curveball.

Rayder Ascanio, SS
Has tools to play shortstop, still make a few too many errors, but just turned 21. Switch hitter, equally sound from both sides. Swing too long, needs more consistent discipline. Flashes good on-base skills.

Tyler Herb, RHP
Will be 25 in April, 3/4 slot, athletic, up to 93 with average slider, fringe-average changeup.  Fits better as reliever where crossfire is an asset.

Joe DeCarlo, 3B
Above-average raw power, has shown ability to work counts and draw some walks. Too much swing-and-miss, mostly due to poor swing mechanics. Below-average glove at third.

Gareth Morgan, OF
Contact rates still alarming, suggesting still very unrefined. Swing still long, pitch recognition remains well below average. 70 raw power, decent athlete, plus arm. Will be 21 in April, needs to show progress.

Latest posts by Jason A. Churchill (see all)


  1. Avatar

    Good stuff.

  2. Ash is a reliever only for me; strike thrower, below avg stuff that doesn’t miss bats.

    Heredia is what he is. No projection left, swing is bad for power. Gamel has a lot more room for growth.

    Starter over reliever in a vacuum, but risk comes into play, too. I’ll take a 60% chance at a late-inning arm within a year over a long shot starter without stuff.

    Morgan still has so much power he has to be discussed for now. Fading fast, obviously, and doesn’t get mentioned at all in even an average system.

    Re: Overton — wrote him up, pasted twice.

    Of the 11 traded away — Jackson and Jackson probably still would have been Top 10s, Gohara would have been 3-4.

    I do not see Vogelbach as necessary to their season. Has potential, but has to earn it. And for me he’s a DH. 1B is a big stretch.

    Simmons I couldn’t rank at all because of his injury and the small setback this spring. No setback? He would have been top 15 since he’s so close to the majors. No surgery at all? Ahead of Vieira.

    Motter is not a prospect even though he qualifies. So little upside and he’s 27. If the player has fewer than 130 PAs and 50 IP he qualifies. MLB’s rookie status.


    Unsworth is a strike thrower without big-league stuff. Despite a performance track record, if I can’t envision a valuable role in the majors, he’s just a not a prospect for me.

    Jason MItchell,

    Gadea would have been Top 10-12. Again, very weak system, but I do like Gadea. Hope he heels fast.

  3. Avatar

    Thank you, Jason, I look forward to this every year! A handful of thoughts from my side:
    1. Ten RHPs, eight OFs, one each of the other positions (LHP, C, DH, 1B, 2B, SS, 3B. Seems to highlight where the acute needs are, for the 2017 draft!
    2. It did seem to me that we traded away most of our high-end LHP depth (although some might question just how “high-end” they were).
    3. No love for Bret Ash? He had a great record at Jackson last year, but I don’t see him on anyone’s Top Prospect lists.
    4. For the guy who may be the third bat on the bench, Heredia seems a long way down.
    5. Is Gareth Morgan (truly) still in the conversation? Not just one of Jack Z’s fantasies?
    6. No love for Jake Zokan? I’m reading he reinvented himself.
    7. Seems like everyone is concluding that Povse was the real “get” in that trade- not Whalen.
    8. Your rationale says “starters over relievers”- then you put Vieira in at #7. Is his upside- as a reliever- that high?!
    9. Plenty of love for Dillon Overton- in fact, he got two (different) writeups! Was one of those meant for a different LHP?
    10. Of the guys we traded away- who would have made your top 10? (You said 11 of your year-end top 25 are gone?)
    11. Looks like you don’t see Vogelbach as critical to their 2017 season!)
    12. Of the unlisted MLB players (Motter, Simmons stand out, for example) who has too much MLB experience to qualify, and who do you just not see as a prospect?

  4. Avatar

    Dylan Unsworth??

Leave a Reply

Your email address will not be published.

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