One third of the way into the current season and it is the pitchers who have held the upper hand, with OPS declining by over 4% from the same period a year ago. Of course, one year ago everyone was trying to adjust to the new timing rules, and it was the batters who evidently had the easier time doing so, pushing up OPS for the first third of the 2023 season by over 4% from the same period the year before. More on offensive trends and adjustments to rule changes are after the jump.
Those whipsaw changes in OPS for the first third of the past two seasons leave us pretty much where we were before last season’s rule changes, with OPS in the doldrums, at levels not seen since the early 1990s. Those results are depicted in the chart below, with OPS results for March, April and May for the seasons of the modern era.
OPS has declined by fully 100 points from an all-time high at the beginning of this century to where we are today. That decline, though, has yielded OPS results today that are similar to those for most of the post-WWII years of the 20th century. However, the same can’t be said of OBP and SLG, the two components of OPS. Here’s the same chart for OBP.
After the offensive explosion of the late 1990s and early 2000s, OBP moved down 20 points from 2009 (.337) to 2013 (.317), and has remained in the .310 to .320 range since then. OBP that low was last seen in the 1960s and early 1970s, and before that only in the deadball era before 1920. Here’s the same chart for SLG.
SLG varies in a much wider range than OBP, so this chart looks very much like the chart for OPS. SLG has definitely fallen off from levels of the early 2000s but is still at or above levels seen for most of the seasons before then. Keeping SLG at its current “high” levels is the trend towards more extra-base hits and, especially, home runs. Here’s that chart.
Home runs and extra-base hits are plotted against the left axis and singles against the right axis. All plotted values are represented as a percentage of total hits. What is worth noting here is that as hits declined over the past two decades, the proportions that are extra-base hits and home runs continued to rise, falling only in the past 5 seasons and still remaining at the same levels of the peak OPS years of the 1990s and 2000s.
I noted at the beginning of this article that this season’s move down in OPS reversed a similar move up that accompanied last season’s rule changes. How unusual are such “whipsaw” effects, when a large move in one direction is followed the next season by a similarly large move in the opposite direction? Here’s that chart.
The above chart is showing year-over-year % changes in early season OPS. The highlighted bars are the “whipsaw” years of changes in opposite directions of 4% or more in consecutive seasons. 2023 and 2024 are the first such seasons in almost 40 years. The other such whipsaw pairs of seasons were:
- 1906-07: Early season OPS declined every season from 1902 to 1908, with the exception of a 5% rise in 1906. All of those declines were reversed with three seasons of rising OPS from 1909 to 1911, the last a whopping 14% rise that returned OPS to where it had been in 1901.
- 1933-34: OPS declined for three straight seasons before rebounding in 1934. A down year (-3.8%) followed by a strong up year (+4.8%) also occurred in the next two seasons (1935-36), but OPS trended mostly down after that, falling almost 10% from 1936 to 1942.
- 1943-44: Wartime restrictions on non-military uses of rubber required a switch to baseballs using the less elastic material balata instead of rubber. The first balata ball design produced a very dead baseball to begin the 1943 season (ten days into the season, there had been a total of two home runs hit in the AL; in the NL, the Reds and Cardinals played a four game series that produced a total of 6 runs). The ball design and manufacture was tinkered with throughout the season until an acceptable product was obtained.1
- 1952-53: The big OPS decline in 1952 was the first of the post-war period and was quickly reversed the next season. Early season OPS rose 9% from 1945 to the 1962 expansion season, mostly in small YoY changes.
- 1968-69, 1970-71 and 1972-73: After big moves down in OPS in 1967 and 1968, accompanied by several spectacular pitcher performances (Bob Gibson‘s 1.12 ERA, 28 CG and 13 shutouts, Denny McLain‘s 31 wins and 28 CG, Don Drysdale‘s 6 consecutive shutouts) in the latter season, new rules lowering the pitcher’s mound and shrinking the strike zone, combined with major expansion (four new teams), produced big moves up in OPS for 1969 and 1970, followed by big moves down in 1971 and 1972. Finally, the adoption of the DH rule in the AL in 1973 produced an OPS spike that season. It’s worth noting that the extension of the DH rule to the NL forty-nine years later failed to produce a similar effect, with early season OPS actually falling by a small amount in 2022.
- 1977-78: Early season slugging jumped up sharply in 1977 to .403, higher than today’s level and the highest seen since the pre-expansion 1959 season. It would be another decade before early season SLG reached the .400 level again. The 1977 season was the year that MLB switched from Spalding to Rawlings to manufacture its baseballs, a change made when Spalding wanted to increase its price by 10% over two years2 (actually, a quite modest increase for those inflationary times).
- 1987-88: Offense exploded in 1987, attributed then to a “rabbit” ball, with early season slugging reaching .415, the highest level since 1930. It was a one-year phenomenon until slugging began a sustained stretch north of .400 starting in 1994.
1 Hynd, Noel, “The inside story about baseball in 1943 was less bounce to the ounce”, Sports Illustrated, May 13, 1985, https://vault.si.com/vault/1985/05/13/the-inside-story-about-baseball-in-1943-was-less-bounce-to-the-ounce (downloaded May 28, 2024)
2 Schoenfeld, David, “The history of juiced balls and how today’s home run binge fits in”, ESPN, Jun 13, 2019, https://www.espn.com/mlb/story/_/id/26960922/the-history-juiced-balls-how-today-home-run-binge-fits-in (downloaded May 28, 2024)