The Aaron Altherr Breakout

Development is rarely linear.  There is no prospect that better exemplifies this than Aaron Altherr.  Altherr was a 9th round pick in 2009 and at the time Perfect Game listed him as 6’1 155lbs and Baseball America cited him as an athlete who hadn’t played much baseball.  He went unranked by Baseball America that offseason, but then we see the non-linearity as his ranking in the Phillies’ system goes 10, 15, 25, 8, 20 from 2010 to 2014.  He is now listed at 6’5″ 215lbs and is putting together a career year between AA and AAA at age 24 hitting a combined .298/.374/.492 across the two levels.  So where does Altherr now stand in the organization.

The Plate Discipline:

The first thing I noticed watching Altherr with Reading this year was that he was laying off a lot more pitches, working deep into counts.  Early the results seemed to skew towards walks ending those counts, but as the season went on he seemed to be drawing walks.  Either way the strikeouts appeared to be down.  This might be a bit of a mirage, but if we look at his career we see that not only is Altherr showing the best walk rate of his career, but near career lows in strikeouts while hitting for more power than ever.

 Year (Team)BB%K%ISO
2009 (GCL)8.716.3.071
2010 (GCL)2.518.2.096
2010 (WPT)7.712.5.138
2011 (WPT)4.417.6.115
2011 (LKW)6.728.8.061
2012 (LKW)
2013 (CLW)8.526.6.180
2014 (REA)5.322.4.163
2015 (REA)10.815.4.188
2015 (LHV)9.319.8.211

*Rehab assignments were removed the data set

In addition to just being more patient, he seems to be recognizing offspeed well and most importantly he is laying off stuff inside on his hands and fouling off the strikes inside.  He will always have a higher strikeout rate due to his physical profile, but more on that later.

The Quality of Contact:

Before going through his batted ball profile, lets just start with the spray chart difference between 2015 and 2014.

Here is 2014 (chart from MLBfarm):

Aaron Altherr (1)


And here is 2015:

Aaron Altherr


Keeping in mind that volume difference between the two spray charts (2014 – 127 games, 2015 – 79 games), we see immediately that he is spraying it to all fields more and less on the ground than in 2014.  So now let’s go to his batted ball profile over his career (stats from minor league central and MLBfarm, there is some margin for error in unknown hit classifications).

2011 (WPT)39.617.329.88.9
2011 (LKW)50.514.623.35.8
2012 (LKW)40.612.638.26.5
2013 (CLW)35.715.337.87.7
2014 (REA)45.413.832.54.6
2015 (REA)
2015 (LHV)36.731.726.75.0

That is a huge jump in line drive rate, and it looks like a good size drop in groundball rate to go with it.  There is likely some variance in the numbers here, but line drives tend to mean Altherr is starting to square the ball up more, and it is showing especially in his doubles as he has the raw power to drive it to the gaps without needing to leverage himself.

What is Physically Different:

Let’s start with the obvious.  He is healthy.  Last year he hurt his wrist in the offseason and missed all of spring training and into the AA season.  Wrist injuries (and in this case a broken bone) can sap a lot of power and contact out of a swing.  Then add in the inability to really work out all winter and then missing spring training and you have a recipe for a bad season.  He is also stronger.  Altherr continues to slowly fill in his lanky frame and the results have been that he has hit the ball harder each year without having to sell out for power.

Then there is the swing itself.  I am far from a swing expert and trying to piece together huge differences between multiple years of swings is difficult when you are looking for differences with an untrained eye.  However, it is fairly clear to see that his swing in 2015 is cleaner, quieter, and smoother.  In the past he has looked disjointed and the added motion seemed to give his swing extra length.  The swing still is a bit long because he is so tall and his arms are so long.  He also doesn’t have an explosive swing or huge bat speed to completely make up for length like Maikel Franco can.  But he seems to have good plate coverage and ability to adjust with the cleaner swing.  Additionally he does not have a huge uppercut and does not get a ton of extra loft, but he has long enough arms that he can get some plane on hits and really leverage out some hits, especially low in the zone.

The Defensive Profile:

Altherr is somewhere between average and above average in center field and can cover ground with long strides and plus speed.  The problem is that his defense is eclipsed by some players in the Phillies’ system (Roman Quinn being primary among them) and a lot of major league center fielders.  Right now he can play center and play it well, but if he loses a step it might not be a long term proposition.  He is a plus defender in either outfield corner and has a plus arm that plays better in right field, but would be a weapon in left field.

Putting Together the Pieces:

Altherr is a major leaguer.  His defensive versatility, ability to hit left handed pitchers very well, and combination of power and speed will keep him near a major league bench for a while.  The bigger question is whether he can be a major league regular.  The stats say he can do it in either center or a corner, but the stats aren’t everything and I personally worry about pitchers getting in on his hands.  There just aren’t many guys who succeed at his size without premium bat speed or coordination, which isn’t to say he can’t do it, it is to say that it is far from a sure thing.  However, the thing that helps is his defense, because he will provide value wherever he is played which means he doesn’t need to be a masher to be valuable.  Additionally the tweener profile has become overrated in the years since Altherr was drafted.  In 2009 center fielders hit .266/.335/.413 collectively and right fielders hit .264/.341/.434.  In 2014 those numbers are .266/.326/.396 and .255/.318/.397 respectively.  Center fielders have reached a level of elite production where the offensive difference from center to a corner is so low the expectations on Altherr’s bat in a corner are lower than ever.

Put this all together and you have a player that is fairly safe to be something at the major league level, but with the upside to be at least a major league regular.  It is difficult to see a star here just because none of the tools are explosive carrying tools, but Altherr could be a very good player very soon if he can make the adjustments to keep going in the major leagues.  He could get a chance to prove that as soon as the Phillies move an outfield (likely Ben Revere) and open up a spot for every day at bats in the majors.


Author: Matt Winkelman

Matt Winkelman

Matt is originally from Mt. Holly, NJ, but after a 4 year side track to Cleveland for college he now resides in Madison, WI. His work has appeared on Phuture Phillies, The Good Phight, and TheDynastyGuru.


  1. Romus

    Very good detailed analysis. Did notice repeat years of ’11 and ’15 saw a precipitous upswing in his lines.
    But agree….his time should soon if not now, with 2500+ PAs in the minors…he paid his dues.
    To increase his versatility and value, at some point in a few years he may want to venture to learn a little first base. He has the right size and I assume good instincts.

  2. Matt, given the above, and if it were up to YOU, when would you promote Aaron?
    1. ASAP no matter what–make space.
    2. As soon as a spot becomes available via trade or injury
    3. Not until after August 1.
    4. September 1
    5. Out of Spring Training next season.

    (My answer to my own question: I’d consider need and space if the situation presents, but I’d probably leave him in AAA through August otherwise,and grant him the September 1 promotion.)

    • Matt Winkelman

      Yeah I am of the same thought. If they trade Revere I would give him the CF job immediately. Otherwise no need to bring him up before September 1 (or whenever AAA season ends)

  3. Frank

    Matt, I want to take this opportunity to Thank You for your fair and objective reports on players. I have been reading your work for some time now and as a father of a minor league player I can’t tell you how refreshing it is to read an fact base report. It is at times difficult to read what fans and even some experts write without really knowing all the facts. I might not agree with everything but I can see your reasoning behind it. I think you haven’t seen the best of Aaron yet and by GOD’s grace he will continue to improve even on the Major League level. Well done Sir and keep up your good work!

    Frank Altherr

  4. Bdinella

    I only see Altherr as great 4th OF. He doesn’t have a tool that will make beat out Quinn and hopefully we get some corner OF with power in the trade for hamels and next drafts. Sorry to go off topic but is it about time to move the 1b up? Stassi, Hoskins and Martin

    • josh

      The one problem with that thought process is, that Quinn or Tocci or whoever aren’t there yet. They might be there or closer next year at this time but the questions abound. Will Quinn come back healthy and fast? Will he continue to hit like this year? Will he be forever hurt? Will Tocci build on a great year?

      There are so many questions with prospects that the immediate value we see in Altherr has to be looked on more positively that others. It’s not like we are talking about a top 10 prospect here like Crawford (although we always have #4 prospect Dom Brown to remind us). Quinn and everyone else have larger more serious questions.