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Diamondbacks Midseason Prospect List: Top Starting Pitcher Prospects

Originally I was going to do another Top 30 list, but instead I have opted to separate the prospects into their respective positions: Starting pitchers, catchers/infield, outfield, and relievers. I figure that will be a more effective list to compare players of a similar position in the system vs. trying to compare players of the same position in a write-up. The Midseason Top 30 will come out at the end of this series of articles. The first list will go over the starting pitchers, due to the level of importance and value to a farm system.

  1. Jackson (AA) RHP Jon Duplantier: Duplantier was MLB Pipeline Pitching Prospect of the Year after pitching 136 innings with a 1.39 ERA between Kane County and Visalia. With a strong 2018, he would have been primed to knock on the door for an opportunity in 2019. A hamstring injury in Spring Training delayed his first start of the season to April 22nd, but then made 7 starts, pitching to a 2.52 ERA with a 2.85 FIP and 2.90 xFIP in 35 23 innings. After his start on May 27th, Duplantier was placed on the DL with biceps tendenitis and has not thrown a single pitch since. In fact, there hasn’t been any news on whether or not his arm is structurally intact but there hasn’t been news about him needing Tommy John surgery either. Duplantier missed 2015 with shoulder issues and had to be shut down after 1 inning with Hillsboro in 2016, so the injury label will ultimately stick with Duplantier until he proves he can handle an MLB workload. When healthy, Duplantier throws the full mix of pitches with 3 potentially plus pitches (fastball, curveball, slider) and an above-average 4th pitch. He has the command to utilize those four pitches effectively, which is why I labeled him as a potential Ace in the making. The only thing that will prevent him from reaching his ceiling will be injuries.
  2. Jackson RHP Taylor Widener: While Duplantier has been on the shelf, the one pitching prospect in AA who’s had a great year is Taylor Widener. Widener was acquired in a 3-team trade with Tampa Bay and New York that sent former Diamondback Brandon Drury to the Yankees and Anthony Banda to the Rays while getting back Widener. Widener had a solid 2017, but has taken his game a giant step forward in 2018. Early in the season, the Diamondbacks kept him around a strict pitch count of 85 since he’s a converted college reliever, but lately have let him go 100+ with each start. As a result, his outings are getting longer and the raw strikeout totals are way up. Currently, he’s pitched to a 2.60 ERA in 86 13 innings while posting a career high strikeout rate of 33.7% and a career low walk rate of 7.6%. Widener throws mid 90s with a devastating slider that is untouchable for RHH and an improving change-up. His change-up has solid fade and downward movement with a 7-8 MPH drop below fastball velocity, which in turn could develop into a serviceable 3rd pitch needed to stick in a rotation. With his breakout year, the odds Widener ends up being a top or middle of the rotation starter is higher than a back-end bullpen arm like Archie Bradley. Widener should finish the season in AA, but the strong season will have him start 2019 in Reno and potentially see action with the MLB club.
  3. Reno (AAA) RHP Taylor Clarke: With Widener’s big breakout, Clarke has slipped to the #3 starting pitcher prospect. Over the last 3 seasons, Clarke has posted similar strikeout and walk rates from Kane County all the way to Reno. His stuff in general doesn’t jump off the page with a fastball in the low 90s and secondary stuff that’s mostly average. His stuff plays up due to having above average command on the mound and the ability to sequence pitches. He tends to be more of a fly ball pitcher, so the home run issue is always a concern on days his command isn’t perfect. Clarke’s had runs of good and bad starts this year, part of the issue of pitching in Reno and the Pacific Coast League in general. For the most part, he’s plateaued as a prospect with very little upside left to gain and will likely settle in as a bottom of the rotation starter long term. On the season to date, Clarke has pitched to a 4.86 ERA with 85 strikeouts to 33 walks in 90 23 innings over 17 starts.
  4. Visalia (High A) RHP Emilio Vargas: Vargas flew under the radar despite a pair of solid seasons in Kane County, but now people are catching up thanks to a breakout 2018. Vargas’ strikeout rate spiked to 33.3% and a walk rate that’s finally dropped below 10% at 9.2% on the season to date. His 126 strikeouts leads the California League as well as his 1.85 ERA over 92 13 innings. Walks and the lack of pinpoint command is his only weakness in the Cal League this year, leading to high walk totals and long innings. Recently, Vargas has been more stingy with the free passes with no more than 3 walks since the calendar flipped to May. Over that time period, he’s pitched to a 1.96 ERA in 69 innings with 94 strikeouts to 16 walks. Due to the drastic improvement in command and control, Vargas easily rises from fringe-prospect to a legitimate prospect with him advancing to AA next season and seeing an opportunity late 2019. He’s eligible for the Rule 5 Draft, so I’d expect the Dbacks to add him to the 40-man roster in November.
  5. Kane County (A) RHP Brian Shaffer: Shaffer was a 6th round pick from last year’s draft, noted for being a control specialist with bottom of the rotation upside. His first full season has been successful, pitching to a 2.70 ERA in 96 23 innings with a 102 strikeouts and 19 walks. His strikeout total ranks 3rd in the organization and easily has the best K/BB ratio of the pitchers on the list. It is also interesting to note that the team isn’t fast-tracking Shaffer like they did for Braden Shipley and Aaron Blair back in 2014, but Shaffer certainly has earned a midseason promotion to Visalia with his strong numbers overall. His fastball sits low 90s with arm side run, a slurvy breaking ball that gets swings and misses, and a change-up that’s improved from fringe-average to average. As he goes up the system, the key will be commanding the ball to the bottom of the strike zone to induce ground ball and weak fly ball contact. Shaffer could end up finishing 2018 in Visalia and 2019 in Jackson before seeing MLB action in 2020.
  6. RHP Jose Almonte: Almonte was acquired in the deadline deal that sent reliever Brad Ziegler to the Boston Red Sox in 2016. Almonte had a successful season for Visalia last year, although was prone to bouts of wildness with 66 walks and 11 wild pitches in 139 13 innings. At the same time, his stuff took a step forward and he finished with 162 strikeouts. Almonte was primed for a potential breakout in 2018, but has not been able to pitch this season to an undisclosed injury.
  7. Hillsboro (Short A) RHP Matt Tabor: Tabor was an upside play in the 2017 draft, as the Diamondbacks picked him up in the 3rd round and signed him for $1 million. He showed flashes in the Arizona League last year, but has stumbled a bit with Hillsboro this season. Tabor is raw as a pitching prospect, likely needing to fill out to 190+ on his 6’2” frame before reaching the majors. When right, he has 3 pitches that can legitimately flash as plus pitches with a mid 90s heater, an excellent change-up, and a breaking ball that’s showing the shape of a slider now these days. Patience will the key for the organization, although Tabor seems to have the right mindset as a pro for improving his game and attacking hitters. He may spend another year in extended Spring Training next season before getting tested in Kane County and starting on the track towards the majors.
  8. Hillsboro RHP Jackson Goddard: The Diamondbacks picked up Goddard in the 3rd round of this year’s draft. Goddard is another upside play, although not nearly as expensive coming out of college vs. high school. Goddard has the size and strength to be a workhorse starter at the MLB level, but control has been a major issue at Kansas. The upside is a middle of the rotation starter with mid 90s heat along with a strong slider and change-up, with the change-up ahead of the slider. Goddard has some injury history, including an oblique injury this year, and inconsistent efforts as he dominated top competition in the Big 12 but also struggled against mid-level competition. Most likely he will see short starts in the piggyback system in the lower minors to close out the year before seeing full season ball next year with Kane County. Goddard has a little bit of extra effort in his delivery, but nothing that creates concern for injuries long term. If the Diamondbacks can get him to throw more strikes consistently, his upside goes from late-inning reliever to middle of the rotation starter.
  9. LHP Tyler Holton: Holton was an ascending talent in the ACC, but tore the UCL in his elbow in his first start of the college season and needed Tommy John surgery. The Diamondbacks saw a lot of Holton while scouting out 2017 Day 1 draftees Pavin Smith and Drew Ellis. In 2017, Holton pitched to a 2.34 ERA with 144 strikeouts and 31 walks in 119 innings as the Ace of the Florida State pitching staff. That season earned him All-American honors from virtually every major baseball publication. Holton had a strong track record of success, immediately contributing as a starter as a freshman before the big sophomore season. The Diamondbacks grab an upside pick at the cost for slot value for their 9th round pick. Since the surgery happened in February this year, Holton is on track to be able to pitch again around May 2019. If he can be the pitcher he was before the surgery, he could prove to be a solid steal in the draft. Holton in 2017 hit the upper 80s with the fastball that touches the low 90s with two plus offspeed pitches (curveball, change-up)

Fringe Starter Prospects: LHP Alex Young, LHP Cody Reed, RHP Ryan Weiss, RHP Jhoan Duran, RHP Jeff Bain, RHP Joel Payamps, RHP Justin Donatella

Possible Bullpen Conversion Projects: LHP Alex Young, LHP Cody Reed, RHP Joel Payamps, RHP Matt Mercer, RHP Harrison Francis, RHP Justin Donatella

The Diamondbacks are developing Alex Young as a starter, although I think he ends up in the bullpen long term, similar to Andrew Chafin. Chafin’s stuff got a notable boost in the pen, with his 2-seam fastball velo jumping from 90-93 to 93-96 to go along with a plus slider. I reason I have Young projected to go to the bullpen is that with a similar repertoire and his minor league numbers not being as good as Chafin’s in a starter role.

Jeff Bain has flown under the radar and has put up strong numbers for Kane County. In 17 starts he’s pitched to a 2.68 ERA in 94 innings with a 91/28 K/BB ratio. Hitters are hitting .229 against him with only 2 HRs allowed on the season. His ground ball rate is a solid 47.1%, so he’s keeping the ball out of the air. The Diamondbacks picked him up in the 16th round in last year’s draft from Cal Poly Ponoma (formerly Cal), so keep an eye on him as a sleeper prospect unless the Cal League completely unravels him.

Of this group of arms listed, Justin Donatella is the closest to MLB action. His stuff is mostly average with an upper 80s heater that’s complemented with a solid change-up. His career arc reminds me a lot of Josh Collmenter, a guy who despite stuff that never jumps off the page kept getting the job done. To overcome an average repertoire, Donatella uses his 6’6” frame to get the ball on a steep downhill plane. He could benefit greatly from a move to the pen where the stuff will play up due to his solid pitchability.