Top 10 Third Basemen Prospects (Preseason 2018 Edition)

by Eric Stashin (aka The Rotoprofessor)

The upcoming class of third base prospects is intriguing, even though many of them aren’t necessarily viewed as “elite”.  After you get past the first two names on the list, you get an interchangeable group of intriguing players who could all become solid Major Leaguers.  Who do we prefer?  Let’s take a look:


1) Vladimir Guerrero Jr. – Toronto Blue Jays
Grade – A
ETA – 2019
Blue Jays’ #1 Prospect

The son of potential Hall of Famer Vladimir Guerrero, as an 18-year old who split time between Single-A and High-A he showed a highly impressive ability to make consistent contact:

  • Strikeout Rate – 11.8%
  • Walk Rate – 14.4%
  • Swinging Strike Rate – 8.4%

That’s right, the teenager walked more than he struck out and showed better numbers upon reaching High-A (7.3% SwStr%).  Add that to the clear power potential, which he should start tapping into as he continues to mature and develop, and it’s easy to envision the sky being the limit.  The only question is where he ultimately fits defensively, as he could shift to a corner outfield spot or first base.  Regardless, he’s one of the truly elite.


2) Nick Senzel – Cincinnati Reds
Grade – A
ETA – 2018
Reds’ #1 Prospect

Selected second overall in the 2016 draft, Senzel is on the fast track (as expected).  Splitting time between High-A (246 AB) and Double-A (209 AB) he hit .321 with 14 HR and 14 SB.  While those are solid numbers, they don’t tell the entire story either:

  • Power – Senzel added 40 doubles and 3 triples, showing that the power is there and will continue to develop
  • Approach – Power hitting prospects tend to struggle with strikeouts, but he showed a solid approach with a 9.6% SwStr% (leading to a 19.1% strikeout rate and 9.7% walk rate)

He’s not going to produce gaudy steal numbers, but a .290/25/10 is possible.  He has the upside to be among the elite third baseman in the game and could arrive early in 2018.


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3) Colton Welker – Colorado Rockies
ETA – 2020
Grade – B+
Rockies’ #3 Prospect

Being a third baseman in an organization that has Nolan Arenado is never going to be viewed as a positive, but Welker played last year as a 19-year old at Single-A so he’s got plenty of time (and could ultimately be used as a key trade chip or at another position).  While he hasn’t developed power yet (6 HR in ’17), there’s potential so with maturity and experience he should learn how to tap into it.  That looks even more promising after he posted a 9.3% SwStr% last season (leading to a 15.1% strikeout rate).

A groin injury cost him most of the second half, which could help cause others to ignore him.  Don’t be surprised if he fully breaks out in 2018.


4) Miguel Andujar – New York Yankees
Grade – B
ETA – Already Arrived
Yankees’ #5 Prospect

He made an impact during his MLB cup of coffee and hit .315 with 16 HR (as well as 6 doubles and 2 triples) over 480 AB in the minors. So why is it that he doesn’t get much love or attention? He hits the ball hard (23.9% line drive rate) and makes consistent contact (7.8% SwStr%), both of which show that he has the potential to carry a strong average. There’s also clearly room for his power to grow, with 25 HR not an unreasonable expectation. Obviously we’d like to see him draw a few more walks, but the potential is there for him to be a solid option at the Major League level. Don’t make the mistake of overlooking him.


5) Michael Chavis – Third Baseman
Grade – B
ETA – 2019
Red Sox’ #2 Prospect

The presence of Devers on the Major League roster is going to slow the ascent of Chavis, but long-term there should be room for both players (one of them could slot in at 1B or DH).  While Chavis did enjoy a breakout campaign in ’17, combining to hit .282 with 31 HR and 94 RBI between High-A and Double-A, there’s one big red flag hanging over him.  Already 22-years old, a 21.6% strikeout rate isn’t going to raise red flags (especially since he improved to 20.4% upon being promoted to Double-A) but a 15.5% SwStr% will.  Against more advanced pitching that type of aggressive approach is going to lead to significant questions.  Now couple that with the potential that he gets home run happy (45.8% fly ball rate at Double-A), and he could easily see his average plummet.  We saw that at Double-A, with a .250 average, and it wouldn’t be shocking to see it continue.

It’s not to say that there isn’t upside, but he needs to modify his approach if he wants to excel at the upper levels.


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6) Austin Riley – Atlanta Braves
Grade – B
ETA – 2018
Braves’ #9 Prospect

For the second consecutive season Riley hit 20 HR, and while his doubles dropped (39 to 19) the raw power is evident and he’s starting to tap into it.  The question is his ability to make consistent contact, as he posted an overall 13.9% SwStr% in ’17 and has struggled at each level he’s played:

  • Single-A (2016, 543 PA) – 27.1%
  • High-A (2017, 339 PA) – 21.8%
  • Double-A (2017, 203 PA) – 24.6%

If you aren’t making consistent contact it’s tough to tap into your power, isn’t it?  It also leads you to believe that his .252 average at High-A is far more believable than his .315 at Double-A (where he benefited from a .393 BABIP).  There is no questioning the upside, but adjustments are needed.


7) Lucas Erceg – Third Baseman
Grade – B
ETA – 2018
Brewers’ #4 Prospect

He spent most of the year at High-A, though he also saw a handful of AB at Triple-A, but turning 23 on May 1 he shouldn’t be long for an opportunity.  He showed a little bit of power potential, with 33 doubles, 1 triple and 15 HR over 496 AB, though we’ll have to closely watch the strikeouts as he advances:

  • Strikeout Rate – 17.7%
  • SwStr% – 12.1%

As it is he posted a .256 AVG at High-A, so an increase in the strikeout rate could have a significant negative impact on the results.


8) Christian Arroyo – Tampa Bay Rays
Grade – B
ETA – Already Arrived
Tampa Bay Rays’ #4 Prospect

He had a disastrous MLB debut, hitting .192 with 3 HR over 135 PA.  That said he didn’t show a poor approach, with a 9.1% SwStr% and 31.3% O-Swing%, and he should be able to improve upon is 23.7% strikeout rate without issue.  He also should carry better than a .231 BABIP, as he’s consistently hit the ball hard in the minors (22.4% line drive rate at Double-A in ’16).

We are still waiting for him to tap into his power, though time will tell if he ever develops into more than a 10-12 HR threat (which may be a long shot).  Couple that with little speed and his overall appeal is going to be limited.  He can handle the bat, and that brings value, but overall his ceiling isn’t as high as some others in the system.


Order Rotoprofessor’s 2018 Fantasy Baseball Draft Guide for just $7.50!!  Click here for the details, but don’t miss out on the best bargain in fantasy baseball preparation.


9) Ke’Bryan Hayes – Pittsburgh Pirates
Grade – B
ETA – 2019
Pirates’ #2 Prospect

Hayes made a leap up rankings this offseason with 27 SB in 32 attempts.  This is one of the biggest questions he faces, as we’ll have to wait and see if it’s an aberration or if the former first round pick can continue to steal 15+ bases as he advances past High-A.  If he can, given the upside and makeup he has the potential to be a .300/15/15 third baseman.

The son of former MLBer Charlie Hayes, Ke’Bryan hasn’t shown the power yet (2 HR in ’17, 8 HR since being selected in the first round of the 2015 draft) but he should add some as he matures.  What he has displayed is tremendous plate discipline, posting a 15.8% strikeout rate courtesy of a 5.4% SwStr%.  At 20-years old that’s highly impressive, and he should learn to drive his pitch when he gets it.  We’ve seen Josh Bell with a similar development path, though they aren’t a perfect comparison.

If we didn’t question the speed he’d be a B+ prospect today, and a strong start will boost his stock into that range.


10) J.D. Davis – Houston Astros
Grade – B
ETA – Already Arrived
Astros’ #6 Prospect

Davis made his MLB debut (68 PA), but is primed to open the year back at Triple-A as he struggled making contact (29.4% strikeout rate, 18.1% SwStr%).  After a 14.4% SwStr% in the minors it’s a significant red flag, though his power potential (30 total HR last season) helps to offset it a bit.  Still, if you are swinging and missing you aren’t going to be able to tap into your full power potential.  He doesn’t have the upside of Joey Gallo, though that’s the profile (.220/25 HR).

Sources – Fangraphs,,

Make sure to check out all of our 2018 Preseason Top 10 Prospect Lists:

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

Order Rotoprofessor’s 2018 Fantasy Baseball Draft Guide for just $7.50!!  Click here for the details, but don’t miss out on the best bargain in fantasy baseball preparation.

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