Is MLB expansion the cure to baseball’s lack of offense?

Baseball is an ever changing landscape of late, but would expansion solve one of its biggest issues?

Baseball had an offensive explosion in 1994, in retrospect, a chemically-aided jolt to the game. Lost among the plethora of dingers whizzing out of ballparks was the run at a .400 batting average by Padres batting champ Tony Gwynn. Far from a steroid-inflated Adonis, Gwynn had already established himself as the best pure hitter since Rod Carew and perhaps even back to Ted Williams. Gwynn went on a hot streak in August, but the player’s strike ended his season with a .394, the closest to .400 since Williams reached the mark in 1941.

Today the .400 mark seems more elusive than ever. The league collectively hit .243 this year, tying 2022 for the lowest AL/NL batting average since 1968. A ban on radical shift was implemented in the hopes of lifting averages, but to little avail. Strikeouts are a big reason why averages have plummeted, but even batting average on balls in play has dropped to .291 – aside from 2022, that’s the lowest mark since 1992.

Averages had dipped in the late 80s and early 90s, but spiked significantly in 1993, just before Gwynn made his run at .400. The culprit? Expansion. Baseball added the Colorado Rockies and Florida Marlins and the National League batting average jumped from .252 to .264 in one year – nearly a 5 percent increase and the largest single-season increase in batting average in the Senior Circuit since 1953.

Could the addition of two more teams help baseball boost offense as it did in 1993? Commissioner Rob Manfred has said baseball will not consider expansion until the stadium situations with the Athletics and Rays are resolved. The Athletics are inching towards a new stadium in Las Vegas, having already departed Oakland, and a potential new stadium for the Rays in St. Petersburg is still up in the air.

In the history of expansion, MLB has never been eager to add to its flock. More teams means more mouths to feed and more competition for talent. For the first six decades of the 20th century, both leagues stood firm at eight teams apiece. They would only begrudgingly add teams if they were threatened – either by a rival league or by litigation.

• The rival Continental League was developed in response to MLB’s slow acceptance of new markets. Backed by legendary baseball executive Branch Rickey and powerful U.S. Senator Estes Kefauver, who threatened anti-trust legislation against MLB, the league sought to replace the Dodgers and Giants in New York and capitalize on emerging markets out west. MLB owners headed them off by expanding in 1961 with the Los Angeles Angels and Washington Senators (replacing the team that departed for Minneapolis) and in 1962 with the New York Mets and Houston Colt .45’s (later renamed the Astros).
• Athletics owner Charlie Finley relocated his team to Oakland after the 1967 season, despite Kansas City taxpayers approving a new ballpark. Senator Stuart Symington of Missouri threatened to hold anti-trust hearings unless Kansas City got a new team, so the Royals were born. The Seattle Pilots joined them in the Junior Circuit, while the National League had to scramble to put teams in San Diego and Montreal.
• The Pilots lasted just one season in Seattle before going bankrupt, and getting scooped up by a Milwaukee car dealer named Bud Selig, who moved the team to his hometown. The city of Seattle sued MLB for breach of contract, forcing MLB to expand again in 1977 with the Mariners and Toronto Blue Jays.
• MLB was again threatened by talk of a rival league in the 1980s. But after owners were found liable for $280 million in damages to the players for collusion, the lucrative expansion fees proved to be an easy way to cover costs, giving birth to the Rockies and Marlins.
• The San Francisco Giants were sold in 1993 to owners who planed to relocate the team to St. Petersburg, only to have MLB block the move. The owners sued, forcing baseball to appease them with a new team. The Tampa Bay Devil Rays and Arizona Diamondbacks began play in 1998.

Potential threats could force baseball to expand again in the near future, whether it is litigation from Oakland or St. Petersburg if they lose teams, loss of revenue from the changing TV landscape, or more labor issues with the players. But could expansion become an opportunity to boost sagging offense?

The addition of two more teams into a league creates around 50 more roster spots for players who wouldn’t otherwise be in the big leagues. Diluting the talent pool has generally favored hitters. Why is that? There is a limit to how much adding a bad hitter can drag down an offense – the worst anyone can hit is .000. But if you add a bad pitcher, there is literally no limit to how bad he can be – you can have an ERA that is infinite.

We can see how past expansions have impacted offense. Here’s how offensive numbers changed in each of the previous rounds of expansion.

The first round of expansion in 1961-62 had a very negligible impact on offense. My guess is that adding four more teams didn’t dilute the talent pool that much – the U.S. population had grown for six decades without any more additional roster spots, plus racial integration had brought a wave of very talented African-American players into the AL and NL. The league was overdue for expansion.

But by 1969, adding four more teams DID have a significant impact on offense. Home runs went up in both leagues. Walks went up. Batting averages went up. The 19 percent rise in runs-per-game across both leagues was and is still the biggest single-season increase in the history of baseball.

The spike in offense in 1993 was not quite as pronounced and can also be explained by adding a ballpark that sits 5,280 feet above sea level. Home runs went up a whopping 32 percent in the National League that year. The 142 home runs hit by the Colorado Rockies in their inaugural season were more than any National League team had hit the previous season. But high altitude only explains part of the offensive spike. If you exclude all games played at Mile High Stadium, the league batting average still rose eight points from .252 to .260 and runs-per-game still rose by 11.9 percent.

The impact on offense in 1998 was negligible, possibly for two reasons. The first is that for the first time, MLB put one expansion team in each league with the Devil Rays in the American League and the Diamondbacks in the National League. There was interleague play, but it was pretty limited, mitigating the impact one team can have in a 14-team league.

The second possible explanation is how performance-enhancing drugs muddy everything up. Offense had already climbed significantly in the years prior to Arizona and Tampa Bay joining the league. And the year after they joined, runs-per-game went up another six percent, a delayed offensive spike.

But generally, expanding teams has led to an increase in offense. Today’s offensive environment looks similar to the 1960s with low runs-per-game totals and very low batting averages, although home runs and strikeouts are significantly higher now. The talent pool may also be at a similar point as it was in the 1960s where there is excess talent relative to roster spots. There has been no expansion for nearly three decades as the U.S. population has continued to increase, plus baseball has seen an influx of more international talent from Latin America and Asia (on the other hand, African-American participation has plummeted).

The evidence also suggests that adding replacement-level pitchers drags down pitching more than adding replacement-level hitters drags down offense. In 2017, Fangraphs writer Kiri Oler found that the disparity between replacement-level hitters and the league average was not nearly as great as the gap between replacement-level pitchers and the league average.

Again, the charts show replacement-level players are below average in all categories, as they should. However, when it comes to starting pitchers, the percentage increase or decrease is significantly larger, with seven of the categories fully eclipsing the maximum percent change for the position player categories and maxing out with a nearly 40 percent increase in home runs per nine innings and xFIP….

Replacement-level hitters are bad; replacement-level pitchers are worse, and because of injuries, even more replacement-level pitchers are required than hitters.

With rosters expanded to 26 since then, and an epidemic spike in pitcher injuries, the gap between replacement-level pitchers and league-average may be even greater now. On the other hand, the widespread application of cutting-edge technology and analytics has allowed teams to staff nearly interchangeable pitching robots capable of throwing high-90s gas with movement. If the Dodgers can win a World Series with an entire starting rotation on the Injured List, perhaps the pitching pool is deeper than we thought.

But even if we assume expansion would dilute pitching more than hitting, would it even give us the desired effects? Runs would likely go up, but more as a consequence of higher home run rates, not necessarily higher batting averages. Perhaps that is fine – fans love offense – but expansion could very well lead to more three true outcome events that have become more tedious as a style of play the more ubiquitous they have become.

In the near future I suspect a pair of teams from some combination of Nashville, Portland, Montreal, Charlotte, Oklahoma City, or Salt Lake City will be part of Major League Baseball. When that happens, offense will likely rise. But if baseball wants to fix the home run/strikeout contests games have become, it will have to look at the root of the problem.