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Mariners To Outright Diego Castillo, Promote Bryce Miller

By Steve Adams | May 1, 2023 at 11:58pm CDT

The Mariners are shuffling up their pitching staff. They’re set to select the contract of top pitching prospect Bryce Miller, as first reported by Joe Doyle of Future Star Series, and they’ve also passed right-hander Diego Castillo through waivers and assigned him outright to Triple-A Tacoma, per Ryan Divish of the Seattle Times (Twitter link).

With that outright, Castillo is no longer on the 40-man roster. He has the three years of service time needed to reject the assignment in favor of free agency, but he doesn’t yet have five years of service, so rejecting the assignment would mean forfeiting the remainder of this year’s $2.95MM salary. As such, he’s sure to accept an assignment to Tacoma and remain with the organization.

It’s been a swift decline for Castillo, who was one of the top relievers moved at the 2021 deadline, going from Tampa Bay to Seattle in exchange for minor league infielder Austin Shenton and righty JT Chargois. Castillo was quite effective in his first season and a half with the Mariners, pitching to a 3.42 ERA with an above-average 25.5% strikeout rate against a slightly below-average 9.4% walk rate. He held opponents to just a .196 average, yielded only 1.06 HR/9 and kept the ball on the ground at a 48.5% clip.

The 2023 season, however, has been a disaster for the 29-year-old Castillo. In 8 2/3 innings so far, he’s walked as many batters as he’s fanned (seven) and also plunked a hitter. He’s already served up homers to two of the 41 batters he’s faced after surrendering only five in 54 1/3 innings (222 batters faced) a year ago. The 94.2 mph average on his fastball, meanwhile, is down 1.6 mph from last year’s mark of 95.8. Overall, he’s sitting on a 6.23 ERA and has allowed 15 of 41 opponents (.366) to reach base.

Any other team could’ve claimed Castillo, but it’s generally rare for other clubs to claim struggling players of this nature when they have a guaranteed contract of some note. The Mariners could’ve waited to make this move but likely saw Castillo’s struggles as a way to open a 40-man roster spot to accommodate their top pitching prospect. If another club had claimed Castillo, the Mariners would’ve been spared the remaining $2.44MM of this year’s salary, but they’ll instead hope he can round back into form with the Rainiers.

Turning to Miller, he’ll make his big league debut when he takes the mound tomorrow against the A’s. He last pitched on April 25, so he’ll be plenty rested. The 24-year-old has had a rough start to his 2023 season in Double-A, pitching to a 6.41 ERA in 19 2/3 frames, but he entered the year among the top 100 prospects at Baseball America, FanGraphs and MLB.com. He currently ranks 92nd, 89th and 85th, respectively on those three lists.

The handful of shaky outings to begin the year, it seems, won’t dissuade the Mariners from hoping he can follow Logan Gilbert and George Kirby to be the next member of the team’s vaunted farm system to step into the Major League rotation. Seattle has already lost Robbie Ray for the season and has seen Chris Flexen struggle in the fifth spot of the rotation, so it stands to reason that Miller could potentially seize a permanent job, if not tomorrow then certainly at some point this season.

Despite his rocky start to the 2023 season, Miller is seen as a potential mid-rotation starter, thanks in no small part to a heater that sits upper-90s and can bump 100 mph. He pairs that with a slider and changeup, and the former college reliever has improved his command as the Mariners have stretched him back out as a starter.

Miller split the bulk of the 2022 season between High-A and Double-A, logging a combined 3.16 ERA with a 30% strikeout rate and an 8.5% walk rate in 133 2/3 innings. He allowed just 0.67 HR/9 and kept the ball on the ground at a slightly above-average rate. And, given that sizable workload in ’22, there’s little reason to think the Mariners will feel the need to monitor his innings total too aggressively this season.

If Miller were to stick in the big leagues, he’d be on pace to qualify for arbitration as a Super Two player following the 2025 season and reach free agency at the conclusion of the 2029 season. Of course, future optional assignments could alter one or both of those timetables considerably.

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Newsstand Seattle Mariners Top Prospect Promotions Transactions Bryce Miller Diego Castillo

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View Comments (30)
Post a Comment

30 Comments

  1. Bnickles127

    2 years ago

    WOW

    3
    Reply
  2. pohle

    2 years ago

    good outright, in the david fletcher vein of underperforming veteran who wouldnt be able to reject the assignment, but also is making too much $ to be claimed by other teams. now seattle has a minor league bullpen arm that has a better shot than most at coming back up and being successful, and bryce miller gets a look at mlb level

    5
    Reply
    • mlb fan

      2 years ago

      It’s getting late early this year.

      4
      Reply
  3. criznit

    2 years ago

    Here is a baseball reference link to the correct Bryce Miller: baseball-reference.com/register/player.fcgi?id=mil…

    Reply
  4. mlb fan

    2 years ago

    The roller coaster, up and down life of an MLB reliever, riding high last yr and this year you’re outrighted completely off the 40 man roster.

    5
    Reply
  5. Seamaholic

    2 years ago

    Wow, Miller kid skipping AAA and not exactly lighting it up so far in AA either, although obviously a major talent. M’s that desperate for immediate help?

    2
    Reply
    • xcfan

      2 years ago

      They could have went with Hancock or Woo from AA, similarly high talent players who have had better success than Miller of late. The only thing Miller has on them is that he threw more innings last year.

      2
      Reply
      • Stevil

        2 years ago

        Worth noting that Divish suggested scouts he spoke with weren’t concerned with his stuff, that he may have just been working on specific pitches.

        He had a solid spring as well, for what it’s worth.

        4
        Reply
        • pohle

          2 years ago

          well see hancock sooner rather than later if he is doing decently, his timer on rV eligibility is the end of this season and the mariners clearly could use some extra innings, with ray out and flexen showing regression.

          1
          Reply
      • lamars

        2 years ago

        Hancock hasn’t fared much better. Pitching to an ERA of 5.40+ and WHIP 1.47 in AA.

        Reply
  6. M'sHacker

    2 years ago

    Never liked Castillo. Would have liked to keep Shenton.

    1
    Reply
    • DCartrow

      2 years ago

      Shant be shuntin’ Shenten.

      2
      Reply
    • jamaicajan

      2 years ago

      Agree.

      1
      Reply
    • HBan22

      2 years ago

      Shenton has sucked ever since the Mariners traded him.

      Reply
  7. Dogham

    2 years ago

    Diego Castillo really hit that wall going about 160mph. Hopefully he can get it worked out in some more non high leverage situations.

    1
    Reply
  8. Stevil

    2 years ago

    I thought Woo might have leapfrogged Miller and Hancock, but seeing one of those three has been widely expected. Miller had a rough start to the year, but was great in his last outing.

    I wouldn’t be surprised if O’Brien has his contract selected as well, with Ray being transferred to the 60, but we’ll see.

    1
    Reply
  9. lee cousins

    2 years ago

    I will take a pitch at this, and hope like Castillo a strike can be delivered. Castillo never makes me comfortable, I digress, when Castillo on he’s good the reason may very well be that the batters never know where the ball is going to go, that’s sorta OK isn’t it? Until he gets behind the count more often then one would like. You know who he reminds me of? Kinda? Ray there I said it. Ray the hard throwing Ray because of it his control becomes at times erratic this however maybe offset by his strikeout performances his style will become over barring in time as it’s has already shown up. Staying healthy will be a challenge, he may be better served in the pen though if he keeps going this way you will run him out of gas, until he goes green.

    2
    Reply
    • chrisjaybecker

      2 years ago

      To me, the comp is Fernando Rodney. When Diego takes the mound, it’s the same kind of Roller Coaster ride.

      Reply
      • lee cousins

        2 years ago

        That’s because there brothers.

        Reply
  10. BPax

    2 years ago

    Castillo was one of the pitchers in MLB with a deliberate routine between pitches. It included tugging, readjusting, etc. I wonder if he’s having issues with the new rules? As an M’s fan, to me he has always had a little Fernando Rodney in him. He mostly got the job done but he took you on a rollercoaster to get there.

    3
    Reply
  11. libertybell444

    2 years ago

    I’d pick him up if I were the Phillies. Work out the kinks in the minors then bring him up and see if he can return to 2020 and 2021 form.

    1
    Reply
  12. joew

    2 years ago

    Castillo i would think would be able to latch on somewhere else pretty easily. Last year he was decent and this year only 9 innings. Seems pretty drastic to send him down for that short of sample? There is probably something i don’t know since i don’t follow them really.

    1
    Reply
    • lamars

      2 years ago

      @Joew –
      Not with him making $2+ million.

      Reply
      • joew

        2 years ago

        @Lamars I would think with his recent season performance someone would take the risk. but again I don’t follow the Mariners. Better than fair shot that I don’t know something 🙂

        Reply
  13. Primitive Screwhead

    2 years ago

    Diego has been an incipient heart attack for fans every time he’s taken the mound for the M’s. Always full of drama: often escapes problems of his own making, but often unravels spectacularly and swiftly. My heart likes this change.

    2
    Reply
    • Fred Park

      2 years ago

      This new guy Bryce Miller might be another “incipient heart attack” kind of pitcher.
      That fastball “in the high 90s that can bump 100 mph” is hard pitching, sure, but it can also be hit hard.
      We have to hope not.
      We want a guy who can pitch hard, like the other Castillo (Luis), but who can get hitters out from the very beginning.
      One of the Mariners’ weakness has been lack of efficiency.
      When that pitch count gets up high too quickly, then problems begin to feed on themselves. Pitchers are only human, and they see they are getting used up too soon.

      1
      Reply
  14. Rosstradamus

    2 years ago

    It’s Miller Time!

    3
    Reply
    • lee cousins

      2 years ago

      Maybe a popular shirt in just another promotion for the M’s

      Reply
  15. cdouglas24000

    2 years ago

    So who’s replacing Castillo in the bullpen? I think berroa should be a good place to start. He still needs to develop a 3rd pitch, but I think he will catch on like brash has. Starts off a lil rough but can be devastating when “on”.

    Reply
  16. zbock

    2 years ago

    That’s not how you use “meanwhile.” It has to come at the start of the sentence, not in the middle.

    Reply

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