Aaron Altherr’s Defense and Player Floor

Most projection systems have been not kind to the Phillies this offseason.  It is not too surprising, the Phillies were bad in 2015 and most of their players were young and inexperienced.  Projection systems in general tend to be conservative in their prognostications, they also are not always the greatest at recognizing breakouts and changes in players.  Which brings me to Aaron Altherr.  Altherr was an extreme bright spot in his 39 MLB games in 2015, after he tore apart AA and AAA over the first 4.5 months of the season.  In general the composite statistics loved him with him earning 1.7 fWAR, 1.7 bWAR, and 1.4 WARP.  All of those over a full 162 games would have lead to completely unreasonable expectations.  Altherr’s bat is still a huge question, and both the numbers and scouts agree upon that.  What strongly seem to disagree on going forward, is his glove.

A lot of Altherr’s success in 2015 was derived from his glove.  He has always been noted as a good center fielder, but his route running improved in 2015 and he showed that he could be very capable defender in both outfield corners.  The numbers in the majors agreed:

Total (LF/CF/RF)

  • UZR (Fangraphs) – 7.3 (3.0/3.3/1.0
  • tZR (B-Ref) – 5.0 (2.0/3.0/0.0)
  • DRS (B-Ref) – 5.0 (1/3/1)
  • FRAA (BP) – 2.8
  • PAA* – 2.0 (-0.7/1.1/1.6)

*PAA is plays above average, a metric designed by Andrew Grant and Scott based on Fangraphs’ Inside Edge fielding data

We have a bit of a range because everyone calculates defense differently and because of Altherr’s small MLB sample size.  Over a full season these metrics say his glove is worth somewhere in the 10-20 runs above average range.  Now this would be among the elite in the game, so it is ok to be a bit skeptical.  But we also  have the observational data that says Altherr is very good in centerfield, so while the numbers may not be exact, we expect them to be favorable.  Here are Altherr’s full projections coming into the season:

  • Steamer (Fangraphs) – 0.6
  • ZiPS (Fangraphs) – 1.6
  • WARP (BP) – 0.4

Now I don’t expect Altherr to be projected to Mike Trout, but these feel low outside of the ZiPS (which feels about right for a system that can see Altherr’s past track record).  Now part of this is that none of them believe in his bat.  They all see his walk rate catering to pre-2015 levels, his power disappearing, and his strikeouts remaining high.  I don’t entirely agree with them on this, but I might if handed Altherr’s career of stats, so I can’t quibble with it too much.  What really confuses me is the defensive projections.  Here are those three projections again.

  • Steamer (Fangraphs) – 3.1
  • ZiPS (Fangraphs) – 8
  • WARP (BP) – -1

Now we see our mystery solved, the huge drop in projections from production is based on low defensive estimates.  If we adjust for what we expect his defense to be, we see Altherr more projected in the 1.5 WAR range.  This will of course fluctuate based on what position he gets playing time at (though in theory his defense should play even more above average in a corner vs center field).  This gives Altherr a floor in the 1-1.5 win range based on his glove alone (and a fairly conservative estimate of his glove, based on 2015 output).  If his bat can replicate some of what he did during any of his stops during the 2015 season, he could be much more valuable than current projections for him.

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. Bary Onyx

    I’m excited to see what Altherr can do this year. He’s not really a prospect so there aren’t high expectations and any positive can be considered gravy. And I don’t care what the scouts and projections say, this guy always seems to hit the ball hard. Can he improve his approach and make more contact in a low stress environment? Here’s to hoping he can.

    Calling it here, Altherr proves to be an under the radar gem. Quality bat with good defense, all around good ball player. Sort of a Jayson Werth type. BANK IT!

  2. I see more Lorenzo Cain with a significantly lower batting average.

  3. phillysf

    I like Altherr, he has steadily improved through out his minor league career and I would expect the same from him in the majors until he probably hits his ceiling which is a great defensive outfielder 260-280 average with 20 hr and sb per year plus or minus 5 , Id say depending on which outfield spot he , will end up being a 2- 3 war player easy