Projecting the Tigers 2013 Run Total

In previous posts, I discussed the linear weights measures - Weighted On-Base Average (wOBA) and Weighted Runs Above Average (wRAA).  Another metric in the linear weights family is Weighted Runs Created (wRC) which estimates how many absolute runs (as opposed to runs above average) a player contributed to his team with his batting.

The wRC statistic is cacluted fairly easily from wRAA and MLB Runs per Plate Appearance (RPA):

   wRC = wRAA + MLB RPA x PA

For example, Tigers slugger Miguel Cabrera had 57.3 wRAA in 697 PA in 2012.  The MLB RPA was .114 so Cabrera had 57.3 + .114 x 697 = 137 wRC which was the highest total in the majors. 

In comparison to wOBA and wRAA, wRC is generally not so useful for assessing the value of or ranking of players because it tends to give too much weight to playing time over performance.  A case in point last year was Delmon Young accumulating more wRC (65) than Andy Dirks (54).  Few would argue that Young was a more productive hitter than Dirks in 2012.  Young had more playing time, but provided below average hitting in those at bats.

The wRC metric is more useful at the team level.  A team's wRC total usually falls within 5% of its run scored total.  The Tigers combined for 763 wRC in 2012 which was 5% more than their 726 actual runs scored, so they were off more than most teams.  What does that tell us about the Tigers?  It suggests that they did not make the most out of their hits and walks and failed to scored as many runs as they should have.  Some reasons for that which have been discussed through the off-season are poor base running, too many double plays and a tendency to hit home runs when nobody was on base.

The wRC statistic is also helpful in projecting how many runs a team will score in the future.  Table 1 below lists Tigers projected players in 2013 and their estimated PA.  In the next column  is the three-year average of wRC adjusted for expected PA.  For example, Cabrera had 412 wRC in 2,033 PA over 2010-2012 which comes out to .203 Runs Created Per PA.  Multiplying .203 times 675 PA (his projected PA for 2013) yields his three-year average of 137.

The final column of the table is a projection for wRC in 2013.  In all cases, it is fairly close to the three-year average.  I adjusted it down slightly if a player is aging and/or coming off a major injury (e.g. Victor Martinez, Torii Hunter and Jhonny Peralta).  I don't expect any players to get significantly better, although I did add a couple of runs for Austin Jackson due to his youth.  The bench is a guess as to who will make the roster and get playing time.  However, the projections would not have been any different if I substituted Danny Worth for Ramon Santiago or Quintin Berry in for one of the outfielders. 

Aggregating all the wRC yields 820 for the team. Remember though that they scored 37 fewer runs last year than the "created".  Will that happen again in 2013?  The Tigers problems hitting home runs with runners on base last year was probably a fluke that should straighten itself out.  However, I suspect the problems with base running and double plays will continue.  That cost the team about 20 runs last year and I'll estimate the same for 2013.  So, 820-20 gives 800 runs scored for the year which coincidentally is exactly the same as the simulated result at Replacement Level Yankees blog.  .

Of course, the analysis above assumes no major injuries, but an an increase of 74 runs (7 wins) would be impressive.  Most of that comes from replacing Brennan Boesch, Ryan Raburn and Delmon Young with Hunter, Martinez and a full season of Omar Infante.  If all goes well, it should be a productive and exciting line-up this year.   

Table 1: Tigers Projected Runs in 2013

Player	PA	Runs Created
		3-Yr Avg*	2013 Proj
Avila	450	61	60
Fielder	700	124	125
Infante	575	63	60
Peralta	575	64	60
Cabrera	675	137	135
Dirks	450	61	60
Jackson	650	83	85
Hunter	600	84	80
Martinez	500	76	70
Pena	200	16	15
Santiago	200	18	15
Boesch	150	17	15
Garcia	150	15	15
Others	375	---	25
Base Running/ DP	---	---	-20
Total Runs	6,200		800

*Adjusted for Expected PA in 2013

Converting wOBA to Runs Above Average

In the previous post, I recommended Weighted On-Base Average ( wOBA) as a measure of overall batting performance.  A limitation of wOBA is that, like OPS, it is a rate stat and does not give a player credit for playing time.  For example, Nationals outfielder Bryce Harper, Reds infielder Jeff Keppinger and Royals utility man Irving Falu all had wOBA's of .352, but had varying numbers of plate appearances:

Harper  597
Keppinger 418
Falu 91

One would guess that Harper contributed the most offensively of the three followed by Keppinger, but wOBA does not tell us that.

We need a counting statistic and the best kind is one that can be expressed in runs.  Once such statistic is Batting Runs which was first presented by Pete Palmer in The Hidden Game of Baseball in 1984.  Tom Tango later re-introduced it in  The Book: Playing the Percentages in Baseball as Weighted Runs Above Average (wRAA).  It is now an important statistic at FanGraphs.   

Getting back to the above example, Harper had 18 Batting Runs in 2012.  This tells us that he contributed an estimated 18 runs above what an average batter would have been expected to contribute in the same number of outs.  Appropriately that was more than Keppinger (12) and Falu (3) accumulated in less playing time.

Percentiles

Table 1 below shows the percentiles for wRAA for players with 250 or more plate appearances (PA) in 2012.  That includes all regulars and part-timers who were considered good enough to see semi-regular playing time.  For example, the 75th percentile for wRAA is 15.  This means that 75 percent of players with 250+ PA had less than 26 wRAA and 25 percent had more than that.  The wRAA column is listed next to the percentiles for RBI to make it a little easier to grasp what's good and bad.  For example, we can see that a 15 wRAA  is equivalent in magnitude to about 73 RBI (although the two numbers measure different things) 

Table 1: Percentiles for Batting Runs

PCTL	wRAA	RBI
100	57	139
90	26	92
75	15	73
50	4	54
25	-5	35
10	-12	26
0	-24	9

 

Calculation

The wRAA metric is based on a player's wOBA and the MLB average wOBA (MLB wOBA) and is calculated as follows:

     wRAA = (wOBA-MLB wOBA)/1.245 x PA.

You may remember from the previous post that 1.245 is the factor which was applied to wOBA to put it on the same scale as On-Base Percentage (this number changes slightly each year).  The MLB average wOBA in 2012 was .315, so Harper had (.352-.315)/1.245 x 597 = 18 wRAA.

More Results

Table 2 below shows the wRAAs for some past and present Tigers.  The final column shows specific percentiles.  For example, Austin Jackson's 28 wRAA  fell at the 91st percentile of all batters with 250 or more PA.  That means he had more more wRAA than 91% of MLB players in 2012.  The percentiles and ordering came out pretty similar to that for wOBA.  There are small differences where players with a lot of playing time moved up and players with less playing time moved down.  The leading Tiger was MVP Miguel Cabrera with 57 wRAA.  He was also the MLB leader.


Table 2: Batting Runs for Tigers, 2012

Player	PA	wOBA	wRAA	PCTL
Cabrera	697	.417	57	100
Fielder	690	.398	46	98
Jackson	617	.371	28	91
Hunter	584	.356	19	83
Dirks	344	.368	15	75
Avila	434	.327	4	53
Infante	588	.310	-2	33
Berry	330	.305	-3	33
Young	608	.305	-5	26
Peralta	585	.301	-7	20
Boesch	503	.288	-11	12
Santiago	259	.253	-13	8
Raburn	229	.256	-18	2