Orlando Arcia and Elite Fielding

Going big picture, with as big a picture as possible, Baseball Prospectus has tracked approximately 95,480 Batter Seasons in MLB history. Through this lens, Orlando Arcia’s 2016 and 2017 Fielding Runs Above Average (FRAA) ranks of 5,858 and 5,733, respectively, do not seem particularly great. There are a lot of MLB players that have been able to post FRAA above 3.5 (6,510), and rookie Orlando Arcia was one of 157 MLB players to have posted FRAA of 3.8; currently, 2017 Orlando Arcia is one of 126 MLB players to have posted FRAA of 3.9. Again, not particularly rare or astonishing.

Arcia FRAA Percentile Raw Ranks
All Fielders (Historical) 93rd 5858 and 5733 of 95480
age-21 Fielders (All) 96th 90 of 2881
age-22 Fielders (All) 95th 189 of 4692
All Shortstops (Historical) 88th 690 and 681 of 5826
age-21 & age-22 Shortstops 93rd 38 and 37 of 629

However, within those groups, Arcia’s age begins to shine, as the shortstop is indeed one of the youngest players to have recorded such defensive brilliance at such an early age. In an age of prospect hype, where fans follow prospects perhaps more than ever, and therefore are desensitized to following extremely young professional baseball players, an age-21 or age-22 MLB player does not seem particularly accomplished; indeed, fans desire player development programs that push players to the MLB by such young ages in order to maximize reserve control during the player’s best years. The facts say otherwise, however, as there are only 2,881 age-21 and 4,692 age-22 Batter Seasons recorded in MLB history, which is a significantly smaller set than “old” ballplayers (witness 8,696 age-27 Batter Seasons). Isolating Arcia based on age (recognizing that he is a special baseball player simply by reaching the MLB during his age-21 season) and fielding (recognizing that his FRAA accomplishments are quite solid thus far) begins to highlight a budding elite defensive profile:

  • In 2016, Orlando Arcia was the second age-21 player to record 3.8 FRAA (after 1989 Junior Felix).
  • This season ranks 90th among 2,881 age-21 players, placing Arcia within the 96th percentile of age-21 fielders.
  • In 2017, Arcia is the fourth age-22 player to record 3.9 FRAA (after 1973 Jim Wohlford, 1976 Johnnie Lemaster, and 2014 Carlos Martinez (!!!)).
  • This season ranks 189th among 4,692 age-22 players, placing Arcia within the 95th percentile of age-22 fielders.
  • These rankings are not simply reflective of Arcia’s playing time, as his age-21 PA rank 468th, and his age-22 PA (thus far) rank 1500th.
  • Even if Arcia reaches 600 PA posting 3.9 FRAA in 2017, that performance would rank approximately 52nd among 200 players, which means that should Arcia’s defensive performance plateau he will still rank among the top quarter of age-22 historical everyday players.

Yet, there is something unsatisfactory about all this, as Arcia is a shortstop and should conceivably be held to a high standard as a glove-first shortstop (which has arguably been his standard prospect profile, even as an elite prospect, for a handful of years now). Conceivably, it would be more beneficial to rank Arcia within the framework of his defensive position, in order to hold him to the standard of a middle diamond position; the logic of the defensive spectrum would hold that if SS is one of the toughest positions on the diamond, of course one could expect Arcia to rank particularly well among all players. So, how does Arcia rank among shortstops?

  • Surprise! Among 5,826 shortstop Batter Seasons, Arcia ranks quite well in terms of FRAA.
  • During his 2016 and 2017 seasons, Arcia ranks 690 and 681, respectively, placing him within the 88th percentile of shortstops. This is not quite as impressive as Arcia’s overall fielding rankings, but it remains quite an accomplishment for the young gloveman.
  • Of course, Arcia’s age is still a factor even within this set of shortstops. Arcia is one of 243 SS to play in the MLB during his age-21 season, and one of 386 SS to play in the MLB during his age-22 season.
  • Grouping these players together to assess a set of 629 fielders, Arcia’s FRAA rank 37th and 38th, placing Arcia within the 93rd percentile of young shortstops.
  • Interestingly enough, Arcia’s bat holds up extremely well against this group of young shortstops, as well.
  • With a current Total Average (TAv) of .247, Arcia’s 2017 campaign ranks 108th among age-21 and age-22 shortstops; last season’s TAv still places Arcia solidly within the top third of age-21 and age-22 shortstops, ranking 202nd.

While some Brewers fans might find Arcia’s glove and bat lacking thus far, taking the big picture showcases several important conclusions:

  • Within the batch of shortstops, Arcia’s glove stacks up extremely well overall.
  • Among extremely young shortstops, specifically age-21 and age-22, Arcia’s FRAA is approaching elite territory.
  • Within this same group of shortstops, Arcia is also quite advanced with the bat, even acknowledging that this is the area of his game where the greatest improvement can be made.
  • (In case you’re wondering, among 1,705 MLB shortstops with 500+ PA seasons, the median TAv is between .230 and .231; if one wishes to be tougher on Arcia, the median TAv among MLB shortstops with 500+ PA seasons over the last decade is between .257 and .258. Of course, within this latter group, the median FRAA is also between -0.6 and -0.8, which should give some idea about how much Arcia’s glove compensates for the bat).

One of the problems with prospect hype is that by the time a young player like Arcia reaches the MLB, fans and analysts already have a handful of years of scouting reports and ceiling or Overall Future Potential assessments within their minds. It is as though a complete player is graduating to the MLB, which is not quite accurate; a professional ballplayer graduates from one professional rank (usually Class-AA or Class-AAA) to another professional rank (the American League or National League) with a set of skills, mechanics, and strategies that must translate to a new environment. Judging from the previous hype, Brewers fans can be quick to write off Arcia based on what they want to draw from his scouting reports; “I knew the glove was overrated,” or “I knew the bat would never come along.” But, contrary to any of those beliefs, Arcia ranks quite well in terms of fielding and offensive performance, especially given his age. This work in progress is already more advanced than the eye test might suggest, which should only leave Brewers fans wondering whether this advanced prospect and above-average MLB player can make the adjustments to become a superstar.

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10 comments on “Orlando Arcia and Elite Fielding”


I’m not sure off the top of my head what the peak age for SS defense is, but I can tell you that defense at SS peaks really early. So even at age 22, we’re probably not too far from peak defensive age.

Mostly, though, have you looked at UZR and DRS? Both have him minus in 2016 and around zero in 2017. Now, I’m not saying that FRAA is “wrong” or a “bad metric,” but if you combine FRAA with DRS and UZR, you are not going to conclude that Arcia is an “elite fielder.”

Nicholas Zettel

Your first point is not true. If you look at the Top Percentile of SS in terms of FRAA, the median age is 27. The median age of the 98th percentile is also 27. Median age of the 95th percentile? Also 27. That’s not an early peak. If you have proof otherwise, I’d love to see it.

UZR/150 and DRS don’t like Arcia right now. Inside Edge loves him, and so does FRAA. So, pick your poison, I guess. If you love zone stats, then Arcia looks bad. DRS, he’s a wash. FRAA and Inside Edge, he looks strong. Draw from that what you like.


” If you have proof otherwise, I’d love to see it.”


“What this chart shows is that there’s a defensive peak for shortstops from ages 22 to 24, and then a long progression downward as the shortstop ages.”

Median (or mean) age for percentiles don’t tell you peak age for anything. There are different players at different ages. The only ones that survive at SS at age 27 or 28 are the best ones, defensively.

In order to estimate peak age or aging curves for anything, you must use matched pairs otherwise known as the delta method. Before you write articles like this I suggest you familiarize yourself with this concept. Tango, me and others have been writing about it since you were probably in diapers.

So, no, I am not wrong. I’ve been doing aging curves and defensive analysis probably since before you were born. ;)


As far as “picking your poison” you don’t get to do that for “research” like this. It is your responsibility as a “journalist” to report all of the relevant data. If all of the data lead down the road of, “we cannot say whether so-and-so is a good, great, average or below average fielder,” which is clearly the case once you note and report the credible fielding data, then it is your ethical responsibility to report that. You don’t get to choose the metric, if several of them are credible, which they all are (DRS, UZR, etc.) that supports your argument while ignoring the ones that don’t. That is irresponsible, unethical journalism. When you partake in that kind of journalism be prepared to be called onto the mat or worse.

Nicholas Zettel

Two things:

(1) I find it ironic that you call me out for failing to use facts, and then misquote the very article you cite. Tango corrects the method to adjust his sampling:

“Note that the rate column for year 1 is marked as “regressed” to avoid confusion. Now, the CHAIN column looks much more reasonable: The peak is from ages 24 to 28, and then the drop is only five plays per year. In the three years leading up to age 24, the gain averages eight plays per year.
The degree of regression will establish the peak age and the slope toward the peak age. I tried different regession values, and it always maxes out at age 28. So, that is one conclusion we can make: On average, shortstop fielding prowess peaks no later than age 28. Recall that, in the first (unregressed) table, the peak age was around 23. So, the true answer lies somewhere between these points (without regression and with maximum regression). The second chart above seems to satisfy this condition.
As for the slope toward the peak, that’s another issue. I can adjust the regression so that we have very little slope (only one fewer out per year), whereas with no regression, the slope was nine outs per year. What is the real answer? I don’t know yet. But, my guess is that the second chart above will likely be very close to the final best answer.”

It looks like a median age of 27 for elite FRAA would be exactly in line with Tango’s findings that shortstop fielding value maxes out at age-28.

(2) I am not a journalist. I am a fan writer. I don’t have any ethical responsibilities. I am writing for fun whenever I have time, and I’m not getting paid to do so. If you believe this is irresponsible, I kindly ask you to read other sources.


I have no problem with the peak age of SS fielding being “between 23 and 28″ as Tango says, although there is some controversy over what that peak age is.

Nicholas Zettel

If you don’t have a problem with that, then why didn’t you just properly cite Tango instead of starting this whole thing?

Tango’s post does not prove what you say.


I didn’t cite Tango because I don’t have everyone’s research in my head at all times. I merely Googled fielding aging curves and came up with the THT article. As I said, there is some controversy about the peak age of fielders. If I took the time to research it again and to look at my own work, I might be able to come up with a fairly reliable estimate of the peak age for SS. But I don’t really have the time right now and it’s not really important at this point in time. Whatever it is, it is and I’m fine with it. If I made a mistake, I made a mistake. Won’t be the first time, nor the last. Nicholas, the only reason I have done baseball research for the last almost 30 years is to advance knowledge in the field. I have no personal stake in any of this. Wherever the numbers take me that’s where I go. Science is all about making mistakes and correcting them. Advancements in science and knowledge in general rarely follow a smooth upward path.

In any case I want to apologize for attacking you personally. That was inappropriate. If there is anything I can do for you now or in the future, such as helping you with any research, let me know and I’d be happy to assist.

Nicholas Zettel

I agree about science, and I’ll be the first to admit I’m not doing science here. I apologize for my short attitude with you.

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