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Return To Average: The Pirates In Week 9

It's been a pretty good day to be a Pirates fan, hasn't it?

I don't know how they have done it, and I have serious questions about whether they can sustain it, but I see no reason not to enjoy it looking at this one last time today:


We all know the caveats. It's only June. They've been 'lucky.' They did this last year. However, I don't know about you, but none of that prevented me from getting goosebumps when #FirstPlaceBucs trended nationally on Twitter seconds after the Reds game ended last night.

There is a lot packed into this Monday's installment of "Return to Average First." The unavoidable theme that emerges from the data is the improbability of what we have seen and the unlikelihood of it continuing. However, in its own way, I think that makes watching the rest of this season unfold even more intriguing and fun. To the numbers:

Runs Scored / Runs Allowed

For the last three weeks I have compared the Pirates offense and pitching/defense to National League average. Specifically, I have tracked the Pirates' offense to NL average runs scored per game, and the pitching/defense to 90 percent of league average runs allowed.

The reasons why I initially started tracking runs scored and runs allowed at these rates is explained here. However, with the Pirates now sitting on top of the NL Central, and with the city starting to buzz with postseason talk, tracking runs at these rates takes on renewed significance. Here is why:

  • In Baseball Prospectus' latest simulation of the 2012 season, 87 wins is the threshold for making the postseason. That seems like a reasonable number and lines up with a many other preseason predictions (Vegas, Yahoo Sports, Sports Illustrated, Bruce Bukiet of baseballphd etc.)
  • Since 1980, 128 National League teams have won 87 or more games.
  • Only 22 (17 percent) of those 128 teams scored less than the league average number of runs.
  • Only five teams (4 percent) scored less than league average runs AND allowed over 90 percent of NL average runs.
  • Only two teams (1.5 percent) scored less than league average runs AND allowed over 91 percent of average runs. Indeed one of those two teams, the '84 Mets, was only one percent below league average runs scored. So, only one team scored scored less than 99 percent of league average runs AND allowed over 91 percent of average runs AND still won 87 games.
  • No team has scored less than 92 percent of league average runs and won 87 or more games.
  • Only six teams (4.6 percent) scored less than 95 percent of league average runs.
  • Only ten teams (8 percent) have scored below NL average runs AND had less than a ten percent run differential between runs scored/NL average - runs allowed/NL average. (For example, the 2011 Atlanta Braves scored 96 percent of league average runs and allowed 91 percent of NL average, for a difference of five.)
  • According to's measure of "Luck" (difference between Pythagorean record and actual record), the Pirates' record is currently the "luckiest" in the National League.

Simply put, for the Pirates to make postseason, it looks like they will need to either limit opponents to less than 90 percent of league average runs, or score a league average number of runs themselves. Unless they are extraordinarily lucky, it is highly unlikely they make the postseason any other way.

Now this week's updated "Return to Average" numbers:


The Pirates played six games this week and scored 29 runs - an average of 4.83 RS/G. Their RS/G for the season increased from 3.06 to 3.24. Last week they needed to average 4.63 runs per game to reach NL average by the end of the season. That number has decreased (for the first time this season) to 4.57. In other words, the Pirates offense will have to score at a rate of 11 percent above current projected NL average for the rest of the season in order to reach a NL average number of runs scored.

(click to enlarge)


Interpretation: the goal is to have the red line meet the green line at the purple line.


The Pirates played six games this week and allowed 20 runs, an average of 3.33 runs allowed per game. Their RA/G for the season decreased from 3.55, to 3.52. Last week they needed to average below 3.77 RA/G to finish at 90 percent of NL average runs allowed. That number has increased to 3.79 (in other words, they gained wiggle room). For the Pirates pitching/defense to finish with 90 percent of league average RA/G, they will now only have to give up eight percent fewer runs than expected NL average for the rest of the season.

(Click to enlarge)


Interpretation: goal is to have the red line remain below the purple line

Offensive Efficiency Revisited

Last week I introduced a measure of offensive efficiency – i.e. whether the Pirates are scoring as many runs as they should, given their total number of singles, doubles, triples, home runs, walks and other offensive events. I measured efficiency by dividing the Pirates actual runs scored by's wRC (Weighted Runs Created) statistic. wRC is a measure of how many runs a team should have scored based on what its hitters have done. In other words, it is an estimate of runs scored based on the totality of offensive events for a team.

A team's offense is efficient if its actual runs are even or above its wRC, or what it should have scored (above 100 percent). It is inefficient if actual runs are below wRC (below 100 percent).

This week I again calculated the Pirates offensive efficiency, and I added the efficiency rate for the Pirates opponents. For comparison's sake, I also calculated the same thing for every team since 1970 (1175 data points, including Pirates opponents). Here are the results:



If the season were to end today, the Pirates efficiency rate would rank fourth best since 1970. Conversely, Pirates opponents' efficiency would rank near the bottom, 1153 our of 1175.


Finally, the question on virtually every Pirates fan's mind is whether the team's early-season success is sustainable. There are a number of ways to examine that question, and I am sure it will be the topic of many future posts by yours truly. For my initial investigation of the topic, I decided to use Fangraphs' "Rest of Season ZiPS Projections" and calculate the number of expected runs scored and runs allowed for the rest of the season, then convert those results into a Pythagorean record.

Every baseball general manager uses some type of projection system to estimate future performance. One of the most well-known is ZiPS (Szymborski Projection System, please read this). It is highly likely that Neal Huntington is looking at very similar projections and using a similar, but more highly-refined methodology as he contemplates the sustainability of this team's winning.

In order to get an idea of how the rest of the season might play out, I took the following steps:

  1. Downloaded the wOBA and ERA projections for every player on the Pirates roster from (If you are unfamiliar with wOBA go here. Basically, it is OPS, but better, and scaled to On Base Percentage.)
  2. Estimated the remaining number of Plate Appearances and Innings Pitched for each player based on his usage so far. Obviously, there will be changes to the roster the rest of the season, and the distribution of playing time will be different than it has been through the first 59 games; however, calculating remaining PAs and IPs in this matter does give us an estimate of how sustainable winning would be with this team exactly as it is.
  3. Generated an estimate of Rest of Season Weighted Runs Created (ROS wRC) for each position player using this formula.
  4. Generated an estimate of Rest of Season Runs Allowed (ROS RA/G) for each pitcher based on their projected ERA, Innings Pitched, plus ten percent, which is the current rate of unearned runs the Pirates are allowing.
Here are the results:

Runs Scored

(ROS = Rest of Season)


Runs Allowed

(click to enlarge)


As can be seen, this method of projection finds the Pirates being outscored 478-370 the rest of the season. The run differential can now be easily transformed into an estimate of wins and loses using the Pythagorean formula

(click to enlarge)

According to the Rest of Season ZiPS Projection system, if the Pirates roster was used in the exactly the same way for the remaining 104 games, we would expect them to finish the season with 71 wins and 91 losses (39-64 the rest of the way). Looking at the average runs scored per game, ZiPS projects a fairly severe regression for the Pirates pitching staff, and a steady, but much smaller, improvement in offense.


That's it for this week's "Return to Average First." We'll see where things stand next Monday after the Pirates play six games against the Orioles (Tuesday-Thursday) and the Indians (Friday-Sunday). The Orioles are allowing 4.45 runs per game, and the Indians 4.42. In terms of scoring, both the Orioles and Indians are slightly below AL average at 4.38 and 4.42, respectively.

Coming up mid-week, I will be posting a study that examines Pirates defense and perhaps some revisions to the projection system outlined above. Hopefully, I'll be able to get that study done before packing the car for a baseball getaway in Cleveland for what should be a phenomenal baseball atmosphere.