Adjusting the Twins’ New Home Run Record

Lost somewhat amid the holiday weekend, the Twins set a new major league record on Saturday. Granted, the mark they surpassed was no long-standing, hallowed standard — in fact, it stood for less than a full year. Nonetheless, with Mitch Garver’s ninth-inning solo shot off the Tigers’ Joe Jiménez, the Twins overtook the 2018 Yankees with their 268th home run, the most by any team in one season. That they left themselves with four full weeks to pad the mark is just one more sign of how over-the-top this this year’s home run totals — fueled primarily by more aerodynamic baseballs, with smoother leather and seams so low that the balls are nearly round — are. The feat deserves a closer look, as well as some perspective.

Here’s Garver’s home run, his second of the day and 26th of the season — in just his 76th game:

Garver’s homers were two of six the Twins hit in their 10-7 loss (a subject to which I’ll return momentarily). His total ranks fifth on the team behind Max Kepler (36), Nelson Cruz (35, in just 101 games), Eddie Rosario (28), and Miguel Sanó (27, in just 87 games). Counting C.J. Cron (24), Jonathan Schoop (21) and Jorge Polanco (20), the Twins are the first team with eight players to reach 20 homers in a season, and they’re the 14th team to have five players reach 25 homers, with multiple candidates to make them the second team to have six:

Three other teams from this season may well join the 5×25 club by the end of this month, namely the Astros (Yordan Alvarez has 22 homers in just 66 games, while both Michael Brantley and Carlos Correa have 19), Cubs (Willson Contreras has 20, and Jayson Heyward 18) and Red Sox (Mookie Betts hit two to get to 25 on Wednesday night, while Christian Vázquez, Michael Chavis, and Jackie Bradley Jr. are in the 17-19 range). Meanwhile, the A’s have three players with at least 25 plus Mark Canha at 23, Ramon Laureano at 21, and both Khris Davis and Jurickson Profar at 19.

When the Yankees hit 267 homers last year, they surpassed a mark that had stood for 21 years, the 264 set by the 1997 Mariners. Sometime in the next week, this year’s Yankees, who have 263 homers, will blow past both. It’s another sign of the times, in that all of the top 20 team home run totals are from the past 24 years, a span that contains 21 of the 24 seasons in which teams have averaged at least one home run per game (1987, and the strike-shortened ’94 and ’95 seasons are the others). Six of the top 20 totals have come from the past five seasons, a period that has produced — and here again I sound like a broken record going on about broken records — four of the top five home run rates, including the high this year of 1.40 per team per game, which is 22.1% higher than last year’s 1.15 per game, and 11.6% higher than the previous record of 1.26 per game, set in 2017. I’ll get to the team leaderboard momentarily, but first, a rerun of a graph I created in June for my “Too Many Homers” piece; at that point, this year’s rate was 1.36 per team per game — about 3% lower than it is currently — but the general trend is really the point:

And now, here’s the leaderboard:

That last column, HR%+, is a normalized stat based upon home runs per plate appearance, with 100 representing league average, 120 a performance 20 percent above that average, and 80 representing one 20 percent below average. We don’t have this as part of our “plus stats” suite, introduced earlier this season, but Sean Dolinar let me order off-menu. LIke our other plus stats, these are relative to the individual league (AL or NL) but not park adjusted; they merely express a team’s home run rate relative to that of their league. By that measure, this year’s Twins have not been as prolific as last year’s Yankees, who hit their homers against a backdrop in which teams averaged 1.15 per game (by plate appearances, which is what’s being normalized, the comparison is 3.73% for this year’s AL versus 3.14% for last year’s). Both of those teams take a back seat to the 1997 Mariners, who homered in a year where teams averaged 1.02 homers per game, and even that bunch of sluggers couldn’t hold a candle to the 2010 Blue Jays, who hit their homers in a season where teams averaged just 0.95 homers per game. If you’re wondering how that stacks up historically, it’s 26th, below a comparatively ancient top 25:

Holy Bambino! Twelve of the top 25 teams are Yankees squads, 10 of them from Babe Ruth’s 1920-34 run; of the other two, the 1916 team featured the AL’s top two home run hitters in Wally Pipp (12) and Home Run Baker (10), while the 1936 team had AL leader Lou Gehrig (49) and rookie Joe DiMaggio (29 homers, fourth in the league). Somehow Baker, who led the AL annually from 1911-14, does not figures in any of the five Connie Mack-managed A’s teams above, and none of those teams were among Mack’s nine pennant winners. On the other hand, the first World Series winners, the 1903 Boston Americans (whose Buck Freeman hit an AL-high 13) are in the house. All of the above teams predate World War II save for the 1947 Giants. Beyond the 2010 Blue Jays, the second-ranked post-1960 expansion team, the 1968 Tigers, is 52nd overall with a 155 HR%+, with the 1980 Brewers (154 HR%+) 56th.

Again, those numbers only express home run rates relative to the league; they don’t include park factors. Our park home run factors stretch back only to 1974; if I incorporate those into the mix, for what we might call “HR%++,” we get this leaderboard for the period:

Now that’s a fun list, with one of the most memorable teams of my youth, the “Harvey’s Wallbangers” 1982 Brewers, third, and their 1980 precursors (managed by Buck Rodgers and George Bamberger, not Harvey Kuenn) first. I’ve excluded a quartet of teams from the strike-shortened 1981 (the A’s at 146, the Yankees at 141, the Expos at 138, and the Brewers at 135), as well as the 1994 and ’95 Indians (135 and 137, respectively). Note that since the park home run factors that I pulled from our Guts pages only go to three digits, I’ve retained the virtual ties in this table, not that it’s a big deal. Since we don’t yet have 2019 park factors, I’ve substituted 2018 ones, but as it is, the top team from this season, the Twins, is tied for 36th with a 130 mark (using a 102 park home run factor). The 2018 Yankees, who had a park home run factor of 112, drop to a tie for 102nd on the list with a HR%++ of 121, while this year’s Yankees are much lower at 114, assuming the same park factor.

Here’s how this year’s 30 teams stack up in terms of both HR+% and HR++%, both of which are normalized to their respective league rates, and the latter of which uses last year’s park factors, which will inevitably change slightly once this season is fully in the books:

While they’ve drawn close to the Twins in terms of raw home run totals — thanks in part to hitting a record 74 last month, to the Twins’ 59 (a total matching the old record, ahem) — this year’s Yankees are actually just the fourth-most potent team when it comes to the long ball this year, accounting for league rates and park factors. That said, they now have a fully operational Judge, and shouldn’t be counted out when it comes to surpassing the Twins, though it’s worth noting the latter does have two additional games to play.

Those Twins, who are on pace to hit 317 homers and have a strong grip on the AL Central lead, are certainly a force to be reckoned with for any team that crosses their path. They will go down in the record books, but homer-wise, they’re not nearly the historical outliers that their final total will suggest. A rising tide lifts all boats.