Baseball’s Designated Hitter Rule Encourages “Beanball”

The benches cleared in the ninth inning at Baltimore’s Camden Yards on July 12 after Yankees closer Clay Holmes hit Orioles batter Hester Kjerstad in the head with a 97-mph sinker. The pitch struck Kjerstad’s batting helmet. Not seriously hurt, fortunately, he jumped up immediately from home plate after dropping to the deck in an unsuccessful effort to avoid Holmes’s pitch.

Orioles manager Brandon Hyde was ejected from the game for protesting the beanball, but the melee already was underway.

July 12’s brawl was a predictable consequence of the American League’s (AL’s) adoption of the designated hitter (DH) rule in 1973. The league’s owners wanted to make baseball games more exciting—more base hits, more scoring—by allowing managers to replace notoriously weak-hitting pitchers (LA Dodger Shohei Ohtani is a rare exception) in the team’s batting order with a pine-riding veteran player still proficient in powering a baseball into the outfield or over the fence.

The AL’s 1973 rule change can be thought of as providing an insurance policy to pitchers, who no longer had to take their turns at bat. The “cost” of throwing at opposing batters fell because pitchers no longer faced the prospect of direct retaliation at the plate if they beaned another team’s hitter.

Although managers sometimes instruct a pitcher to throw at an opposing hitter, it is more often true that pitchers themselves try to brush a batter back from the plate, change his stance, or otherwise disrupt his rhythm by sailing a pitch close to his body, especially when he has hit effectively in earlier plate appearances. Even if the pitcher does not consciously intend to bean the batter (doing so gives the hit player a free pass to first base) and merely wants to cool off a “hot bat,” such tactics increase the likelihood of hitting opposing batsmen.

Economists attribute the post-DH-rule change in pitcher behavior to “moral hazard,” a problem endemic to insurance markets. After an insurance policy is issued, the insured event is more likely to occur because the policyholder no longer bears the full cost of his or her actions. Risk-taking is encouraged because the cost of an accident is shifted onto the shoulders of fellow policyholders who pay insurance premiums but do not submit claims.

The concept of moral hazard can be traced to health economist Mark Pauly, who, in 1968, applied economic reasoning to explain why insured patients visit their healthcare providers more frequently than uninsured ones. One of the most well-known extensions of the idea is called the “Peltzman Effect” (after University of Chicago economist Sam Peltzman), who studied state-based mandatory seatbelt laws when seatbelt-equipped vehicles were first sold. Peltzman reported evidence showing that drivers who buckle up are less likely to be killed in road accidents (as argued by the mandates’ proponents), but that seatbelt wearers are more likely to be involved in less serious (nonfatal) crashes as well as accidents resulting in pedestrian injuries or property damage.

That is clear evidence of moral hazard: Other things being the same, drivers who buckle up are less careful behind the wheel—less attentive to traffic and weather conditions—because they are “insured” (face a lower risk of death) if an accident happens.

The same is true of baseball pitchers. The DH rule protects them against being beaned by their opposite number if they hit one of the opposing pitcher’s teammates in the batter’s box, purposefully or not. Analyzing data on all hit batsmen from MLB’s earliest days at the start of the Twentieth Century until the mid-1990s, aggregated by season and league, two coauthors (Brian Goff and Robert Tollison) and I found, in an article published in the July 1997 issue of the journal Economic Inquiry, that, during the DH era, AL batters were significantly more likely to be hit by pitches than were NL batters—about 10 to 15 percent more likely, on average. (The time series of AL and NL hit batsmen tracked each other quite closely before 1973.) That evidence was confirmed by J. C. Bradbury in 2007 (see his The Baseball Economist: The Real Game Exposed), who conducted the same statistical tests using a much more fine-grained play-by-play dataset.

Major League Baseball’s National League (NL) did not adopt the DH rule in 1973 but did so as part of a collective bargaining agreement signed before the start of the 2022 season. The chances of NL batters being hit by pitches should have risen since then, closing the 20-year gap with the AL. 

The DH rule protects pitchers from personal retaliation in the batter’s box. As the events at Camden Yards on July 12 illustrate, a batter’s teammates can express their ire at a pitcher who hits one of their own by rushing the mound en masse. The pitcher’s teammates unsurprisingly race from the field and the dugout to defend him from shoves and thrown fists. 

Bench-clearing brawls are as old as the game itself. We should expect more of them in the National League now that it has mimicked the American League’s DH rule.