Trend Spotting: Jesus Aguilar and a case study in ballpark effect
Tracking Jesus Aguilar throughout the minor league system it appeared that he had two tangible skills worth monitoring, which if developed would carry him to the big leagues. The first being the power tool and the second being an on base ability which saw gradual improvement. For most Indians fans however, it was the power tool which launched Aguilar on to the prospect scene in 2011, where he hit 26 home runs between rookie league, low-a and high-a.
As an organization which seems to be constantly starved for power, even accepting the massive power decline league wide, Aguilar’s start was incredibly promising. Then 2012 and 2013 arrived, and while the slugging production was still above average, we witnessed a decline in home run production that coincided with improving plate discipline, spiking his OBP ability.
The generally accepted wisdom was that Aguilar had sacrificed power for an increase in contact and on base ability, perhaps on the margins this is correct but it appears to be generally misguided. I find Aguilar to be an interesting case because he displays the challenges of measuring prospect development in highly variant settings.
Specifically from arm chair statisticians, yes you can point the finger directly at me, as I at points voiced concern with both Aguilar’s slugging percentage and home run production in the daily ATF. I was misguided but it is clearly Aguilar’s meal ticket to the big leagues as defensively he projects best as a full time DH, a trait many Indians seem to share.
Unfortunately, the same ballpark variance that deflated Aguilar’s statistical output in 2013, inflated his prospect status in 2014. In many ways, one of the inordinate challenges to evaluating Indians minor leaguers offensively is the Akron-Columbus transition. While I am usually data driven, its imperfections must be noted, and prospect development is one of its greatest gray areas. Indeed, the more I look at data on development, the more convinced I am of the importance of organizational scouting and having eyes on a player over an entire season.
With this understanding I will outlay Aguilar’s productions over the course of his career and then talk about the specifics of Canal Park in Akron and Huntington Park in Columbus.
As an example of the production gap for Aguilar in an albeit limited sample he has posted an extra base hit every 9.38 plate appearances in Columbus, where last year in Akron it was one in every 12.88. Another interesting note are his home/road splits. In 2013 he posted an almost neutral production line home and away, which was unlike prior performance.
Whether it is the stability of the batter’s eye, comfort, home cooking or one of many other factors, Aguilar has traditionally hit far better at home. This makes 2013 an outlier season which is definitively linked to the home effect of the home park.
If we look at his home/road splits to this point in 2014 they are incredibly disparate. In Columbus Aguilar posted a slash line of .313/.384/.586, on the road it sits at .214/.371/.304.
I will attempt to add brevity in this article in order to avoid being a painfully redundant human being, though it is one of my trademarks.
First a note on park factor: This is data where 100 is neutral, anything sub 100 is pitcher friendly and above 100 is batter friendly. Furthermore, any park more than 10 to either side are rather large shifts from the norm.
Columbus’ overall park factor sits at 105, with the home run park factor at 128, yes 128! This is an immensely favorable park to hit in, having inflated failed prospects like Andy Marte and Matt LaPorta to promotions after past failures in the big leagues.
As for Akron, well a pitchers paradise it is, with an overall park factor of 99, and an HR park factor of 84. The transition from Akron to Columbus borders on absurdity as it is perhaps the greatest HR park factor gap in any system. Thus using OPS, which is reliant on slugging percentage can even be fairly deceptive when talking about a prospect's development, specifically when talking about the upper levels of the Indians system.
Which is why I ultimately surmise that evaluating prospects, specifically power prospects through only statistical evidence is particularly challenging in the Indians system due to the park variance at the upper levels.
A few things that may only interest me:
- Carlos Santana’s BABIP currently sits at .177. ( Yes I know everyone is tired of BABIP but this is mildly important.)
- Santana is one of only three qualifiers in MLB with a BABIP below .200. In fact he is one of only twelve with a BABIP below .250.
- While BABIP is rarely volatile in its regression to the mean during the season, there is no doubt that “luck” has had an effect.
- We can also concede a decline in quality contact but not to the extent that would cause this.
- With an absurdly poor BABIP, Santana is still among the top 5 Indians in OBP with more than 120 plate appearances. This speaks both positively of his walk rate and negatively of his peers.
- Fun with WAR: Michael Brantley’s 2013 WAR 1.7. Through 51 games in 2014: 1.8.
- According to UZR and UZR/150 the Indians are the second worst defensive team in MLB, though I must confess watching them makes one wonder how anyone could be worse.
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A further note that I wish to include is that while I do not have milb park factors by batter handedness, Progressive Field is not kind to right handed hitters, with a 89 for home runs.
Ostensibly, Progressive Field and Jesus Aguilar are not a dream marriage but he is still talented enough that he may have some success.
Chisenhall's career fWAR prior to 2014 (203 games): 1.1
Chisenhall's 2014 fWAR (41 games): 1.4