What is the Maximum Number of Home Runs a Player Can Hit in a Season?
How much higher than Barry Bonds’ 73 can we go?
2019 was a record-breaking year for home runs in Major League Baseball. Batters smashed a total of 6,776 homers, the equivalent of 1.395 long balls per team per game. 2017 is the only season that comes within even 1,000 dingers of that mark.
Given how many home runs are hit in today’s game, we could once again see some huge individual home run totals. In fact, Barry Bonds’ all-time record of 73 home runs in a season should be for the taking.
When it does go down, how high can the new record go? What is the maximum number of home runs that can be hit in a season?
First things first — how many opportunities to hit a home run can a player receive in a season? The MLB record for plate appearances in a single season belongs to Jimmy Rollins, who stepped up to the plate 778 times for the Philadelphia Phillies in 2007.
That’s a good starting point, but we can’t quite use that number. Rollins was a leadoff hitter, which naturally maximized his number of plate appearances. The best power hitters, on the other hand, are typically placed either third or fourth in the lineup, giving them a greater chance of hitting when players are already on base.
Barry Bonds actually was first in the batting order in 462 games during his career. However, they almost exclusively came at the beginning of his career. 1990 was the final season when Bonds batted leadoff in multiple games. To remind you, his 73 home run season came in 2001, and his streak of four consecutive National League MVPs came from 2001–04, more than a decade after he stopped batting leadoff.
During these years, Bonds batted either third or fourth in every game he started. Luckily, using the average number of plate appearances for every starter in the order, we can estimate the maximum number of times a power hitter could step up to the plate in a season.
The above chart shows us that while the first spot in the batting order gets an average of 4.65 plate appearances per game, the third spot gets 4.43, or about 95.3% as many expected plate appearances. By multiplying that rate by Rollins’ record of 778 plate appearances, we can estimate the maximum number of plate appearances for a power hitter in a season to be 741.
So, there you have it — 741 is the theoretical maximum amount of home runs a player could hit in a season.
Well, not really.
If a player was able to hit a guaranteed home run on every plate appearance, teams would intentionally walk that player every time he came up in the order. After all, giving up one base is much better than four.
The statistic which describes how many bases a player gains per at-bat is slugging percentage. A perfect slugging percentage — a home run (four bases) every at-bat — would be 4.000.
While they are plate appearances, walks don’t count as at-bats. Still, in terms of slugging percentage, we can think of a walk as being equivalent to a single, which earns one base and a slugging percentage of 1.000. This means that if a player’s slugging percentage goes above 1.000, it makes sense for an opposing team to walk them every time.
(Note: in certain situations, such as a tie game with the bases loaded in the bottom of the ninth, our player would never be intentionally walked. That being said, for the purposes of our experiment, the 1.000 threshold makes sense to use.)
We can’t have that, so we need to manage the number of home runs our optimal home run hitter hits to stay under that threshold. Given 741 plate appearances, our batter would need to hit a home run on just under one-fourth of their at-bats to avoid being walked. This puts our new maximum at 185 home runs in a season.
It’s an improvement, and you could technically use this figure, but it’s still unrealistic. Reaching 185 home runs in a season would require every hit by a player to result in a home run, which is impossible.
Even in the Home Run Derby, where MLB’s greatest power hitters are lobbed meatballs primed to be crushed to a different zip code, plenty of balls fail to make it out of the park. It’s difficult, even for the best of the best, to make consistent, perfect contact. And that’s just in an exhibition environment. A professional baseball game is a different animal entirely.
What we need is an estimate of an all-time great power hitter’s slugging percentage with their home runs removed. Let’s go back to our friend Barry Bonds.
In 2001, Bonds posted a slugging percentage of .863, which is another all-time record. However, if you remove the 73 home runs, that figure drops to around .295.
If we give our optimal home run hitter that slugging percentage on all at-bats not resulting in home runs, we can calculate our new maximum total by solving the following equation:
(4x+.295(741-x))/741=1
This results in x equaling 141. Still, we aren’t done. By this point, we’ve reached the maximum number of home runs for a player with 741 at-bats in a season. But that’s not where we started — that 741 figure originally stood for plate appearances.
As I mentioned earlier, walks don’t count as at-bats. Neither do plate appearances that end in a sacrifice bunt or sacrifice fly, the batter being hit by a pitch, or the batter being awarded first base due to interference or obstruction, although these instances make up a small minority when compared to walks.
Roughly eight percent of all MLB plate appearances end in walks, with that number slowly increasing due to the rise in the three true outcomes (home runs, walks, strikeouts). However, for power hitters, who pose more of a threat to collect multiple bases each time they’re up to bat, that number rises as pitchers become more hesitant to throw in the strike zone.
For an all-time power hitter like Barry Bonds, things get simply ridiculous.
In 2001, Bonds walked 177 times, comprising more than 26% of his total plate appearances. Astonishingly, Bonds would actually walk in a higher percentage of his bats for each of the next three seasons, maxing out in 2004, when he walked 232 times, the most ever in a single season and over 37% of his plate appearances.
Even in his final season, 2007, during which he turned 43 years old, Bonds walked more than once per game.
Bonds could have decided to swing for the fences on pitches outside the strike zone, probably adding a few home runs to his total at the cost of his overall efficiency, but even that wouldn’t eliminate his walks entirely. Sometimes, teams wouldn’t even let Bonds swing the bat.
Bonds was intentionally walked 688 times during his career, which, along with his 762 home runs and 2,558 total walks, is another all-time record. During his 2004 season alone, Bonds was intentionally walked 120 times. For some perspective, that intentional walks number by itself would place Bonds fourth in the MLB for total walks that season.
That year, Bonds was intentionally walked with the bases empty 19 times, something which is completely unadvisable mathematically. But in 2004, the numbers didn’t matter. People were scared of Barry Bonds.
These high walk totals limited Bonds’ ability to record at-bats and hit homers. In fact, if all 664 of Bonds’ plate appearances in 2001 resulted in at-bats, his pace of 73 home runs in 476 at-bats would have seen him hit roughly 102 home runs that season.
Extended to our maximum of 741 plate appearances for a power hitter, Bonds reaches 113.6 home runs, which is starting to get close to our 140 number.
But we can’t ignore all of the plate appearances that result in official at-bats. In 2001, 71.7% of Bonds’ plate appearances were at-bats. This means that instead of 741 plate appearances, we’re only working with 531.
Edit the earlier equation to 4x+.295(531-x))/531=1, and our final estimate for the maximum number of home runs a player can hit in a season comes out to be 101.
Depending on how you want to define what is possible, you might opt for either of the 141 or 185 figures. Still, we’ve at least managed to set a floor. A player hitting triple-digit home runs in a season could theoretically occur.
Will it, though? That’s another question entirely.
At the beginning of this piece, I somewhat misleadingly described Bonds’ 73 home run mark as for the taking. Judging by the overall totals from 2019, which saw 24% more home runs hit than in 2001, this would seem to be the case.
Yet, for a season that felt like one huge Home Run Derby, no individual player posted an earth-shattering mark. MLB’s leading home run hitter in 2019 was New York Mets rookie Pete Alonso, who recorded 53 homers on the season.
This isn’t to lessen Alonso’s achievement — 53 is a big number, one that’s been bested just 26 times in MLB history. Any time someone hits 50 home runs in a year, they’ve had a special season.
But still, 53 isn’t up there with the all-time single-season totals. It’s not even close to Bonds’ 73 in 2001, Mark McGwire’s 70 in 1998, or Sammy Sosa’s three seasons out of four with at least 63 homers around those same years.
Babe Ruth even managed to hit 60 home runs in 1927, a season where teams only averaged .373 home runs per game. If you scale those numbers up to match the rate at which teams knocked balls out of the park in 2019, Babe Ruth managed to hit the modern equivalent of 224 home runs that season.
Of course, a number like that is laughably unattainable, but Ruth’s actual total of 60, which was now set nearly a century ago, has still only been reached by four other players, and three of them — Mark McGwire, Sammy Sosa, and Bonds — were caught for using PEDs.
Because of this, some still consider Roger Maris’ mark of 61 the single-season record. The fact that no one over the last 58 years has been able to match Maris while playing clean is remarkable. Players are currently hitting home runs at an almost 50% higher rate than back then.
Even Maris’ number is somewhat up for debate, as he received the benefit of his Yankees playing a modern 162-game schedule while Ruth’s Yankees in 1927 played just 154 games. Through his team’s first 154 games in 1961, Maris only hit 59 home runs.
As this graph shows, over the last century, the rise of home runs hit by the average team per game has far outpaced the marginal growth in leading annual home run totals for an individual player.
This supports the idea that we’ve basically reached the peak of human home run hitting potential. The highest number a player can realistically hit in a single season is around 60.
The main change over time is that while the ceiling isn’t getting higher, the average player has become a better power hitter. Changes in rules, playing equipment, and coaching stemming from an increased understanding of analytics have made hitting home runs easier and more common than ever before.
League leaders in any given year still hang in the 40s or perhaps even 50s, but an average player who starts most of his team’s games will now finish in the low 20s, rather than the teens or even single digits of prior seasons.
So while teams are hitting more home runs than ever before, for top players, not much has changed. It might be fun to think about, but unless there are significant modifications to the way baseball is played, a player cracking 100 home runs or more in one season just isn’t going to happen.
Connor Groel is a writer who studies sport management at the University of Texas at Austin. He also serves as editor of the Top Level Sports publication on Medium, and the host of the Connor Groel Sports podcast. You can follow Connor on Medium, Facebook, and Twitter, and view his archives at toplevelsports.net.
