A look at Wins Above Replacement: Ruben Tejada

When Ruben Tejada has been healthy, he's been a very good shortstop. So good, in fact, that Mets fans have begun to forget about the guy who used to play shortstop for them. See? Forgotten.

The old guy is currently hitting .264/.336/.378, with 22 RBI and 27 XBH in 384 PA's. 

The new guy is currently hitting .325/.381/.405 with 12 RBI and 13 XBH in 182 PA's. 

Though a smaller sample size, it's not very tough to see who's doing better at the plate. But let's make two further comparisons:

FIRST: How does Tejada at 22 compare to the old guy at 22?

Well, he won't play more games, because Jose (Who-se?) Reyes appeared in a career high 161 at age 22. In those games (733 PA's), he hit .273/.300/.386, with 58 RBI and 60(!) stolen bases. It is important to note here that many SABRmetricians discount the value of steals (an opinion I share. Argument: The Mets stole 130 bases last year, and scored 718 runs. They're on pace to steal 85 this year, and score 742, their highest total in five years). Anyway...

The people who spend their time collecting all these stats so people like me can whine about them have come up with a stat called Wins Above Replacement (WAR), which basically sums up the overall value of a player. The nice thing about it is that you can use it to compare seasons and careers of multiple players; its formulated to be consistent and comparable from year to year, and, to a limited extent, from position to position (If someone is a 5 WAR second baseman, it doesn't really hold that they would be a 5 WAR center fielder. Also, it isn't necessarily fair to say that a 4.0 WAR first baseman is a better or more valuable player than a 3.7 WAR shortstop, as first base is the far-easier defensive position). Also, it's important to note that WAR is a "counting" statistic; it doesn't fluctuate like batting average. It accumulates or subtracts based on a player's performance relative to "replacement-level". In other words, for a player's WAR to decrease, they would have to play worse than replacement-level.

There are two primary sources for WAR: Fangraphs and Baseball-Reference. Each site calculates it somewhat differently, so someone's WAR on Fangraphs (denoted fWAR) wouldn't compare directly to someone's WAR on Baseball-Reference (denoted rWAR). You can find more information on how they're calculated on their respective sites.

Jose Reyes' age 22 season earned him a 1.4 rWAR and a 2.3 fWAR. Ruben Tejada has a 1.6 rWAR and a 1.3 fWAR this year. According to Baseball-Reference, Tejada's play in 41 games alone contributes more value to the Mets' success this year than Jose Reyes' play in 161 games did in 2005! On Fangraphs it isn't yet, but Tejada is certainly on the pace to top Reyes' season. To provide a closer comparison, however, I'm going to modify these a little bit. I'm going to call this "Marginal WAR", or MfWAR and MrWAR. I'm going to do this by dividing their WAR by plate appearances, to calculate how valuable each player is on a direct proportion to playing time.

Jose Reyes:

MfWAR: 0.00314

MrWAR: 0.00191

Ruben Tejada:

MfWAR: 0.00714

MrWAR: 0.00879

Depending on which site you use, Ruben Tejada has been between 2.27 and 4.6 times more valuable than Jose Reyes on a per-plate-appearance level (NOTE: This does not mean that each Ruben Tejada plate appearance is so much more valuable than one from Reyes. I chose to use PA's as I feel they best represent a player's portion of offensive and defensive playing time.) Were Tejada to play at this level for an entire season, it would translate to roughly 5.5-6.0 rWAR (Baseball-Reference defines 6.0+ as "all-star"). Is this sufficient to say that Tejada is an all-star caliber short stop? Certainly not in itself, though it does provide a good context about his level of play. 

To consider his "all-star" eligibility, we should look at how he stacks up to other major league shortstops. Which brings us to...

SECOND: How does Tejada compare to other MLB Shortstops in 2012?

Ruben Tejada is currently the second-youngest everyday shortstop in the major leagues (He is older than Starlin Castro of the Cubs. He is also older than Atlanta's opening-day shortstop, Tyler Pastornicky, who last appeared as a pinch runner on May 30th and has been replaced by Andrelton Simmons.) Tejada presently ranks 14th in fWAR (tied with Jose Reyes and Alcides Escobar) and 9th in fWAR (tied with Zack Cosart) in the MLB. (Fun Fact: both sites rank him above Derek Jeter!). However, in both cases, the bulk of players above him have played significantly more. So, for fun's sake, let's break down the top 15 players on each scale by Marginal WAR:

(Click to enlarge)

[NOTE: National League shortstops are in bold, American League shortstops are italicized]

We can draw two quick and dirty conclusions from this chart:

1. The two sites do show inconsistency in their grading of shortstops. Troy Tulowitzki, for example, fails to even show up in the Baseball-Reference list.

2. Though his playing time has been limited, Ruben Tejada has the second-highest MbWAR and fifth-highest MfWAR among NL shortstops.

Certainly due to the uncertainties of baseball, and to his level of inexperience, it's unfair to use this data to say that Tejada is an all-star caliber shortstop. However, it does seem fair to say that Tejada, when on the field, has certainly played like one. Let's hope that it's a trend that continues, because he looks to be headed for a bright and prosperous future.