The Impact of the 2023 Rule Changes on MLB Statistics in Historical Context
What impact did the 2023 MLB rule changes regarding defensive shifts, pitcher and hitter clocks, baserunning changes, etc., have on statistics such as batting average, stolen bases, and more?
Issue #127
On November 20, 2022 I published an article titled “MLB Trends and Five New Records Set for Hitting, Pitching, and Fielding Rates in 2022.” Now that the 2023 regular season has concluded, I wanted to do an update to that article—especially given the several rule changes we had this year regarding defensive shifts, pitcher and batter time clocks, limits on pickoff moves, larger bases, etc.
These rule changes were put in place to tweak the game in various ways: to try to raise batting averages, increase stolen bases, and most of all, decrease the overall length of games. So what has been the impact on these and other common statistical metrics?
Length of Games
Starting with the length of games, the results are clear: games were much shorter in 2023 than in recent years. Prior to 2023, the length of an average MLB game had bloated to a record 3 hours, 11 minutes in 2021, before moderating only slightly to 3 hours, 6 minutes in 2022. If you factor out relatively rare extra-inning games, those durations were 3:10 and 3:03 respectively.
In 2023, the average length of a MLB game was only 2 hours and 42 minutes (or 2 hours, 39 minutes if considering only nine-inning games). The last time we saw average game times that short was in the mid-1980s. So clearly the rule changes—most notably, I assume, the pitcher and batter clocks—have had a big impact here.
Sidenote: I’m not seeing a dramatic change in the durations of all games vs. 9-inning games only. As a result, I don’t think the other recent rule change—the so-called “Manfred Man” whereby each team gets a free runner on second base at the beginning of each turn at bat in extra innings—has had much of impact on game lengths overall. It has had some impact, but there are times where both team score a run in the 10th inning because of that free baserunner in scoring position, a run that might not have happened otherwise—thereby extending the game further. Therefore, that remains the one recent rule change that I remain personally opposed to, as I think it does little good and runs contrary to the core notion in baseball that you need to earn your way on to the bases (whether through your accomplishment as a hitter or the failures of the opposing side, including strategic decisions in the case of intentional walks).
Batting Averages
While no longer the critical statistic that it long was, most of us still track batting average with some interest. This metric usually starts out pretty slow in April and May, but in 2023 it was pretty consistent with each overall monthly average being between .247-.250.
The overall 2023 MLB average came in at .248, five points higher than in 2022 and the highest since the .252 overall average in 2019. This isn’t a huge difference, but perhaps the change in the degree of defensive shifting allowed, and the net result of the pitcher and hitter clocks, had some impact here. If batting averages stay at .248 or rise further in subsequent seasons, then a good case could be made that the rule changes have curbed the several decade slide from the high range of .265-.271 that we saw from 1993-2000.
Home Runs
We saw a drop in HR rate in 2022 to 1.07 per team per game, the lowest since the 1.01 hit in 2015, and significantly lower than the 1.39 hit in 2019. But 2023 saw an uptick to 1.21, similar to the 1.22 rate we had in 2021. It should be noted for context that all of these recent rates are higher than even the steroid era, which peaked at only 1.17 in 2000).
I’m not sure what this uptick in 2023 can be attributed to—the net effect of pitcher and hitter clocks, yet another change in the baseball itself, or some other factor. For me, for now, this change in HR rate just is what it is—and I await the next few seasons to see what happens next in this regard.
Stolen Bases
I wrote in November of last year that “the trend towards fewer and fewer stolen bases has perhaps finally ended, as 2022 saw an uptick to 0.51 SBs per team per game, the highest since the same level was achieved in 2018. While still quite low by recent standards, it is worth remembering that it is nearly twice the all-time low of 0.26 achieved in 1950. It just feels low compared to the Rickey Henderson / Tim Raines / Vince Coleman days of the 1980s. Interestingly, the peak of that era on a SB per team per game basis was 1987—the same fluke year when HRs spiked.”
Well, the rule changes for 2023, such as limitations on pick-off moves and slightly larger bases, certainly encouraged more base stealing attempts, as well as a record-setting success rate. The SB per team per game rate jumped from 0.51 to 0.72, the highest since 1997. That is still below the modern-era high of 0.85 in 1987, and far from the running-centered game of the dead-ball era over 100 years ago—but it is an impressive jump nonetheless.
It wasn’t just a few of the games top thieves doing all the dirty work. Yes, Atlanta’s Ronald Acuña Jr’s 73 SB in 2023 is the most since José Reyes swiped 78 in 2007. And Oakland’s rookie OF Esteury Ruiz also impressed with 67 to lead the AL. Four others also had over 41, the total that Jon Berti led the majors with in 2022. The tenth highest SB total in 2023 was 33, compared with only 25 in 2022.
The increase in SB was widespread, with the Reds leading the way by nabbing 190 in 2023, compared to the Rangers leading with only 128 in 2022. All but 8 teams in 2022 had under 100 SB—in 2023 it was almost the inverse as only 9 teams failed to get over 100 steals. The lowest was the Giants with only 57 SB in 2023, followed by the Angels with 72 and the Rockies with 76.
2023 didn’t just see an increase in stolen bases, it also set a record low in the caught stealing rate. So runners weren’t just attempting more steals because of the rule changes, they were being successful a noticeably higher percent of the time too. An all-time low CS rate of 24.3% had been recorded in 2021, but this dropped to 19.8% in 2023—a significant, recording setting change as this chart clearly indicates.
Strikeouts
Unlike stolen bases, strikeouts didn’t change too much in 2023 compared with recent years. The rate per team per game of 8.61 was a bit of an increase from 2022, but didn’t top the all-time high of 8.81 in 2019. The overall, several-decades-long trends of hitters swinging for the fences and the increased specialization of relief pitchers are keeping strikeout rates historically high.
Complete Games
Speaking of relief pitching specialization, that of course has an impact on starting pitchers hurling complete games. Another factor is teams’ increasing concern—especially given ever-ballooning player contracts—for pitch counts and the health of their valuable assets. One can argue about the extremes of Nolan Ryan’s durability (while pitching more innings) vs. Jacob deGrom’s lack thereof (while pitching in today’s environment)—but the fact is that 2023 saw a new record set for the fewest complete games in a full season.
The rate of 0.01 complete games per team per game appears unchanged from the past few years, but when we look at the raw numbers we find a record was in fact set in 2023—barely. There were only 35 complete games thrown in 4,860 total games, compared with 36 in 2022. Leaving aside the short 2020 season, the last two years have come up noticeably below the totals of 50, 45, 42, 59, and 83 going back to 2016—the first year ever with less than 100 complete games thrown.
Fielding Errors
Another overall record was set in 2023, and this is one I think just about everyone can be happy about. Only 0.52 errors were made, per team per game, in 2023, a bit lower than the 0.53 errors committed in 2022. For those more familiar with the Fielding Percentage statistic, that too set a new all-time record in 2023 with a .986 mark, one tick above the .985 we saw in 2022 and 2021.
Both of those 2023 numbers are all-time records, and are a continuation of a nice downward trend we’ve seen over the past five years, and indeed a longer trend dating back to the mid-1970s.
All data is from Baseball-Reference.com, and also their subscription service Stathead.com. If you are a big sports fan, be sure to check out the latest features at Stathead and the Sports Reference family of sites.
Did you know? I wrote a book with the same title as this Substack newsletter / blog: Now Taking the Field: Baseball’s All-Time Dream Teams for All 30 Franchises. It was published in early 2019, by ACTA Sports, the publisher of the annual Bill James Handbook and other popular titles. You can learn more about it at www.NowTakingTheField.com, or buy directly at Amazon and other booksellers.
