Top 10 Left-Handed Pitching Prospects (Preseason 2017 Edition)

by Eric Stashin (aka The Rotoprofessor)

This past year’s draft saw two potentially elite southpaws be selected in the first round, though they are hardly the only high-end left-handed pitching prospects.  With a few potentially impact starters set to debut in 2017, as well as potentially the “next Julio Urias”, there are some impressive names on this list.  Let’s take a look:


1) A.J. Puk – Oakland A’s
Grade – B+
ETA –2018/2019

The sixth overall selection in the 2016 draft presented himself extremely well in his first taste of professional baseball, with 40 K vs. 12 BB over 32.2 IP.  Many felt that he had the best stuff of any pitcher in the ’16 draft, and there was a time he was expected to be the first overall selection.  At 6’7” he certainly has the size and if his changeup develops as expected, he’ll carry three above average pitches with him.

That makes the hard thrower an ace in the making, especially if Oakland gives him the time to develop.  At 21-years old the team may want to force the issue, but we all know that it can take time for taller pitchers.  As long as they are patient, he’s going to develop into one of the top pitching prospects in the game.


2) Jason Groome – Boston Red Sox
ETA – 2019
Grade – B+

Selected 12th overall this past year, the southpaw didn’t pitch much after being drafted though did manage 10 K over 6.2 IP.  He has the size that team’s look for from starters (6’6”) and at 18-years old he should add some more weight as he matures (220 lbs. already).  He already brings a big fastball and has the potential develop into an absolute steal.  It’s going to take time, but as a lefty he could help form a dominant top of the rotation before too long.



3) Kolby Allard – Atlanta Braves
Grade – B+
ETA – 2018

Selected in the first round of the 2015 draft, Allard impressed last season compiling 95 K and 25 BB over 87.2 IP.  His groundballs dropped significantly after reaching Single-A (0.66 GO/AO over 60.1 IP), which will be something to watch as it could obviously lead to potential home run issues moving forward.  Outside of that, though, what’s not to like?  He owned a 9.8 K/9 vs. 2.6 BB/9, and the potential is there for a significantly higher groundball rate.  In other words the potential is there to flash all three skills, and in a system flush with pitching talent his upside may be the highest.


4) Amir Garrett – Cincinnati Reds
Grade – B+
ETA – 2017

A popular breakout candidate heading into 2016, Garrett split time between Double and Triple-A showing strong numbers at both stops:

  • Double-A (77.0 IP) – 1.75 ERA, 1.03 WHIP, 9.12 K/9, 3.27 BB/9, 1.04 GO/AO
  • Triple-A (67.2 IP) – 3.46 ERA, 1.17 WHIP, 7.18 K/9, 4.12 BB/9, 1.22 GO/AO

Obviously the drop in strikeouts and rise in walks will be something to monitor closely, especially the control as he owns a minor league career 3.7 BB/9.  At 6’5” he is on the taller side, so it’s not a complete surprise that it’s taking him a little bit longer to discover that aspect of the game.  It should come in time and with his stuff/athleticism the upside of a top-of-the-rotation arm is real.


5) Josh Hader – Milwaukee Brewers
Grade – B+
ETA – 2017

After thriving at Double-A (0.95 ERA over 57.0 IP) Hader stumbled in the Pacific Coast League (5.22 ERA over 69.0 IP).  He showed strikeouts at both levels (K/9 of 11.53 and 11.48), though the control ballooned after the promotion (3.00 BB/9 to 4.70).  With a minor league career mark of 3.8 BB/9 there’s reason to think it’s a bit of an aberration, especially after a 3.0 mark over 104.0 IP in 2015.

He also struggled with poor luck while at Triple-A, including a .345 BABIP and 63.2% strand rate.  We’d like to see a few more groundballs (0.92 GO/AO over his minor league career), especially in Milwaukee, but there’s enough to like with his strikeout rate and solid control.  If the control continues to be an issue it’s possible that he’s transitioned to the bullpen, but for now that’s not going to be a consideration.



6) Sean Newcomb – Left-Handed Pitcher
Grade – B+
ETA – 2017

The biggest problem with Newcomb is his control, as he posted a 4.6 BB/9 in ’16 and owns a minor league career 4.7 mark.  Sure he can strikeout out a significant number of batters (9.8 K/9 last season), but he has taken a step back against more advanced hitters and he could continue to regress with another promotion.  It’s something worth watching, though you’d expect there to be enough (though if he can’t throw strikes it won’t matter).


7) Braxton Garrett – Miami Marlins
Grade – B+
ETA – 2020

Selected seventh overall in 2016, he was widely regarded as having a high floor for a high school pitcher.  That’s thanks to an advanced curveball and the expectation that he develops and adds a bit more velocity to his fastball.  The latter is an assumption, but at 6’3” and 190 lbs. it’s easy to envision.  Like most young pitchers he will need to develop a third pitch to help keep opponents honest (something he’s already doing), but he has ample time for that.


8) Luiz Gohara – Atlanta Braves
Grade – B+
ETA – 2018

Is he the “next” Julio Urias?  Now 20-years old, the southpaw made his mark in his 13 starts across two levels of Single-A:

1.81 ERA, 1.15 WHIP, 81 K, 23 BB, 1.68 GO/AO

That’s certainly the type of skill set we look for, the biggest question centers around his workload as he threw just 69.2 innings.  Considering that was a career high, it’s fair to wonder how long it’s going to take for him to make a significant impact at the Major League level.  That said, he’s heading in the right direction as he took a step forward with his control (the other significant concern hanging over him).  We need to give him time to develop, but the upside is there.



9) Justus Sheffield – New York Yankees
Current Grade – B+
ETA – 2018

A first round pick in 2014, Sheffield was another key piece to the trade that sent Andrew Miller to Cleveland.  The big question facing him is his control, with a 3.8 BB/9 this past season despite spending most of his time across two levels of Single-A.  There also is an issue with his stature, as you know there are going to be questions as to whether or not a 5’10” pitcher can handle a starter’s workload or if he will ultimately find a home in the bullpen.

There’s no questioning the potential (129 K over 125.1 IP last season), it’s just a matter of answering the questions.


10) Tyler Jay – Minnesota Twins
Current Grade – B+
ETA – 2018

It wasn’t many innings (14.0), but his 5.79 ERA for the 2015 first round pick has to give us a little concern…  OK, not really.  That’s especially true after he posted an 8.78 K/9, 2.71 BB/9 and 1.34 GO/AO over 69.2 IP at High-A.  A college closer, you know he’s going to be a little bit of a work in progress until he proves capable of holding up to a full workload on a regular basis.  Of course even if he stumbles he could transition into a closer of the future type, though the Twins are going to give him an opportunity to stick in the rotation and see if he can thrive.

Just Missed – Max Fried (Atl, B+), Stephen Gonsalves (Min, B+)

Sources –,, Frangraphs, Baseball Reference

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Grading System:
Grade A – Elite Prospects (aka potential future perennial All-Stars)
Grade B – Above Average Prospects (aka above average Major Leaguers, could develop into a potential All-Star)
Grade C – Average Prospects (aka solid, though unspectacular)
Grade D – Nothing More Than Roster Filler
Grade F – Move On

Make sure to check out all of our 2017 Prospect Rankings:

AL EastAL CentralAL West
Baltimore OriolesChicago White SoxHouston Astros
Boston Red SoxCleveland IndiansLos Angeles Angels
New York YankeesDetroit TigersOakland A's
Tampa Bay RaysKansas City RoyalsSeattle Mariners
Toronto Blue JaysMinnesota TwinsTexas Rangers
NL EastNL CentralNL West
Atlanta BravesChicago CubsArizona Diamondbacks
Miami MarlinsCincinnati RedsColorado Rockies
New York MetsMilwaukee BrewersLos Angeles Dodgers
Philadelphia PhilliesPittsburgh PiratesSan Diego Padres
Washington NationalsSt. Louis CardinalsSan Francisco Giants

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