How have MLB's new rules changes affected the game so far?

This week, Playing Pepper will take a break from pure fantasy content to look at how baseball’s new rules have affected the game on the field and in the box score.

Baseball’s biggest story entering 2023 was the implementation of several new rules designed to speed up the pace of play and increase the number of hits and stolen bases. It’s still very early of course - Wednesday, April 12 was the 14th day of the season - probably too early to begin comparing this year’s numbers to those of past complete seasons. But if we only look at the first two weeks (in this case defined as the first 14 dates with at least one game) of any campaign, we can see how dramatically things have changed from this point in 2022.

Time of Game

As of Wednesday, the average nine-inning MLB game in 2023 took a bit over two hours, 37 minutes to finish, almost a full half-hour less than the average over the first two weeks of the 2022 season (3:07). It probably goes without saying that this is the largest year-to-year decrease in MLB history.

Since the end of World War II, the next biggest early-season year-to-year drop in average time of game took place between 1962 (2:41) and 1963 (2:29). The latter season marked the beginning of a five-year mini dead-ball era that culminated in 1968, the “Year of the Pitcher.” The Cubs led the way in pace of play early in 1963, averaging 2:20 per nine-inning game over the season’s first two weeks. Meanwhile, across town, White Sox left-hander Juan Pizarro was one of the biggest beneficiaries of the lower scoring environment, putting up a 0.00 ERA in 18 innings pitched over that same span.

At this point I will admit to being biased on the topic of time of game. A large portion of my regular job at Elias consists of waiting for games to finish at the end of the night, so any decline in TOG makes my life easier. Having said that, I still think this is an extremely positive development for MLB. I love baseball, but there was never really a good reason for games to become as long as they have this century. This trend has very likely depressed interest in the sport, particularly among younger fans. The difference so far in 2023 is so great that even a casual observer would probably notice, even if they had not seen the actual data. The quickening of games should end up being the largest effect of this year’s rules changes, but the topic has already gained quite a bit of attention and analysis. How have these changes affected baserunning, batting and pitching statistics?

Stolen Bases

Multiple changes to the rulebook, most notably larger bases and limits on the number of pickoff attempts allowed by pitchers, have contributed to an increase of 0.225 stolen bases per team per game from this point last season (0.464 to 0.689). The last time MLB experienced such a rise in early-season steals was from 1928 (0.408/game) to 1929 (0.640). That figure eventually dropped to 0.544 steals per game for AL/NL teams over the full 1929 campaign, but even that lower number would not be matched again across the majors until 1974 (0.640 SB/G for the full season). Two players tied for the MLB lead in stolen bases over the first two weeks of the 1929 season: Reds center fielder Ethan Allen and Dodgers second baseman Jake Flowers.

Ethan Allen, not to be confused with the leader of the Green Mountain Boys or the present-day furniture chain, is probably best known today as the longtime head baseball coach at Yale, where he coached future President George H.W. Bush. Allen would go on to swipe a career-high 21 bags in 1929.

Jake Flowers played sparingly for the rest of that season, finishing 1929 with nine stolen bases in 46 games. Flowers won the World Series as a reserve for the Cardinals in both 1926 and 1931.

Batting Average and Slugging Percentage

The rise in stolen bases seems to have gotten more attention so far, but year-to-year improvements in other offensive numbers have been nearly as notable. The MLB-wide batting average has jumped from just .230 over the first two weeks in 2022 to .250 in 2023, an increase of nearly 20 points. Similarly, slugging percentages have gone up by 41 points, from .369 early in 2022 to .410 so far this year. Both of those increases are the third largest since 1900 over the early portion of any one season to the next. Let’s take a quick look at the top two.

1920–1921

Early-season batting and slugging averages went up by 31 (.255 to .286) and 71 (.332 to .403) points respectively between 1920 and 1921. The first of those years is widely considered to be the start of the Live Ball Era, when Babe Ruth swatted 54 home runs (out of 369 total in the American League that year, an astounding 14.6%) in his first season with the Yankees. But it wasn’t until the latter campaign that the rest of the sport began to emulate Ruth’s slugging style. When the Bambino set a single-season home run record for the third straight year by belting 59 four-baggers in 1921, he accounted for “only” 12.4% of the AL’s homers.

Dodgers’ third baseman Jimmy Johnston led the majors with a .513 batting average over the first two weeks of the 1921 season. Johnston, who turned 30 years old that May, went on to finish his eighth MLB campaign batting .325 with a .460 slugging percentage and five home runs, all of which shattered his previous highs in those categories of .291, .361, and one.

Who led MLB in slugging percentage over the first two weeks in 1921? You guessed it – Babe Ruth (1.028).

1933–1934

Leaguewide offensive numbers tend to fluctuate from year to year more in baseball than in other sports, for reasons that, in retrospect, are sometimes clear, sometimes not. Case in point: the leaguewide batting and slugging averages over the first two weeks of the 1933 season mysteriously fell to .244 and .337 respectively. Both figures were baseball’s lowest in over a decade. The next year’s averages rebounded to .265 and .393, much more in line with other seasons of that era.

Cleveland left fielder Joe Vosmik led the majors with a .442 batting average over the early portion of the 1934 schedule. Vosmik would go on to bat .341 with 78 RBIs and only 10 strikeouts that year, playing for manager and soon-to-be Hall-of-Famer Walter Johnson. Only two other players since 1934 have finished a season with as many RBIs and as few strikeouts: Tommy Holmes in 1945 (117 RBI, 9 SO) and Lou Boudreau in 1948 (107 RBI, 9 SO).

Giants right-fielder and future Hall-of-Famer Mel Ott led the majors with a slugging percentage of .875 over the first 14 dates of the 1934 season. Surprisingly, only one of Ott’s five home runs over that span came in his home park, the Polo Grounds, where Ott belted 323 of his 511 career homers. No other player has hit as many as 300 dingers at any venue (a future edition of Playing Pepper will have much more on the former horseshoe-shaped Stadium in Upper Manhattan).

ERA and WHIP

All these increases in offensive numbers are good for batters, but of course not so great for pitchers. Through Wednesday, the MLB-wide ERA and WHIP figures of 4.46 and 1.35 were up significantly from the first two weeks of the 2022 season (3.77, 1.25). The year-to-year bump in early-season earned run average is the second largest over the last 60 years (+0.74 from 2008 to 2009), and the 0.10 increase in leaguewide WHIP over this portion of the schedule is the largest since 1982 (+.0.13), my first season as a baseball fan (about which I have written at length).

The highest WHIP by any pitcher who threw at least 12 innings over the first two weeks of the 1982 campaign belonged to Brewers right-hander Pete Vuckovich, (2.08) who went on to win the Cy Young Award that year (although with a high-for-any-era 1.50 WHIP)! Vuckovich is probably more famous today for playing Yankees’ slugging first baseman Clu Haywood in the 1989 classic film Major League.

Walks?

I have seen a few people whom I respect claim recently on Twitter that bases on balls are up quite a bit in 2023, but the evidence suggests that there has not been much of a difference. Over the first two weeks of the 2022 campaign, 9.16% of plate appearances ended in a walk. This year, that number is a nearly identical 9.20%.

Coming up

Next week, we will look at whether early-season wins by relief pitchers can predict success in that category for the rest of the year.