The average number of runs per game per team has fluctuated throughout baseball’s history. There have been declines attributed to better gloves and the introduction of hard-throwing set-up men and closers. There have been increases linked to such things as the lowering of the pitcher’s mound, the introduction of the designated hitter and artificial turf.
Since 1901, the average yearly rate of change has been about five percent either way. Here are the fluctuations over the past 15 seasons (2012 totals through May 7):
On a team basis, run production can fluctuate from year-to-year based on things as tangible as changes in ballpark dimensions, and as variable as batting average on balls in play. The following table shows the change in run production from 2011 to 2012 for each team, measuring against the average across the majors, with the year-to-year change in performance relative to league average. For example, the Cardinals averaged 4.70 runs per game in 2011, 10 percent better than the league average of 4.28. So far in 2012, they’ve averaged 5.55 runs per game, a gaudy 32 percent better than the league mark of 4.20. So, from year-to-year, they’ve improved 22 percent relative to the league average.
For the Braves, the improvement can be tied to the turnaround of their entire outfield. Last year’s leaders in outfield production had 14 homers (Jason Heyward), 57 RBIs (Martin Prado), and a .278 average (Michael Bourn, in 53 games upon his arrival from Houston). This year, all three starting outfielders have OPS+ safely over 100 (Prado 105, Bourn 125, Heyward 133). The entire team’s OPS with runners in scoring position has risen from .714 to .752, while their BABIP has increased from .284 to .311. (One might expect some regression in that area as the season moves forward.) The Braves are averaging nearly 1.5 runs per game more than last year, and are up 37 percent year-to-year against the league norm. (Note: The Braves have declined from 5.43 runs per game to 5.19 in the few days since the original research was completed.)
The 2011 version of the Pirates was no juggernaut on offense, averaging a scant 3.77 runs per game (12 percent below league average). However, no one could have foreseen the utter collapse of any semblance of an attack, as Pittsburgh has mustered only 2.79 runs per contest so far. That rate is 34 percent below league average, making for a 22 percent decline year-to-year against the league norms. Compared to 2011, the Buccos are getting much less production from catcher Rod Barajas, second baseman Neil Walker and new shortstop Clint Barmes. They stole bases at a fair clip last year (108 out of 160 for 68 percent). This year they are 14 for 25 (56 percent). They’ve also forgotten about walks, averaging nearly one less per game. One area where they might improve over the remainder of the season is BABIP: this year’s .278 mark pales next to last season’s .301.
So where do the Braves and Pirates rank all-time in terms of changes in year-to-year offense? Here first is the list of those teams that experienced at least a 30 percent improvement versus the league average:
The Braves are sitting amongst some rare company. There hasn’t been an improvement like this since 1978, when the Brewers added just over one run per game to their offense, while the overall league average dropped by roughly 0.4 runs. The 1903 New York Giants benefited from a career year from outfielder Roger Bresnahan (.936 OPS) and the first full season of manager John McGraw, helping lead the squad to a .111 increase in OPS (.570 to .681).
Now here’s the list of those teams that experienced at least a 30 percent decline versus the league average:
The 1903 season saw the American League adopt the "foul strike" rule, which may account for scoring across the league dropping by 0.8 runs per team per game. The 1914-15 A's fell off when Connie Mack broke up a World Series team, selling off several of his stars. The 1943 Red Sox lost stars Johnny Pesky and Ted Williams to World War II.
At "only" 22 percent, the Pirates have to improve their underperforming to crack this list. Assuming the majors’ average runs per game stays at 4.20 for the rest of the year, they’d have to lower their runs per game to 2.43 to achieve a 30 percent drop relative to the league. It seems unlikely they’d score only 395 runs in the entire year (162 * 2.43). But, that’s why they play the games.