Baseball has seen many changes in the past 100 years. Some changes are significant enough, retrospectively, to define an era. There was the Deadball Era from roughly 1901 to 1919, characterized by an emphasis on pitching, defense, and a low run-scoring environment. The Liveball Era began in 1920, ushered in by Babe Ruth, cleaner baseballs that were easier for batters to see, and rule changes like banning the spitball. When the offense started to overpower the game, more changes were made to temper that environment, like the introduction of the ground-rule double in 1931. Before that, a ball that bounced on the field and over the fence was considered a home run.

There’s Jackie Robinson’s debut in 1946, and the following years when African-Americans finally were permitted to play in the majors. There’s expansion, the lowering of the pitcher’s mound, the introduction of the designated hitter in the American League, free agency, more expansion, newer ballparks, PEDs, testing for PEDs, and an ever-expanding strike zone — all marking the beginning of other, overlapping eras. And then there’s the sabermetrics revolution — using advanced statistical modeling and analysis to construct rosters, manage bullpens, and deploy extreme defensive shifts.

All of these changes in baseball and yet, for the last 100 years, the offensive hierarchy among defensive positions has remained pretty much the same. First basemen, right fielders, and left fielders produce more offense than the average player; catchers, second basemen, and shortstops produce less. It was that way in 1914, in 2014, and in nearly every season in between. Clean ball, dirty ball, higher mound, lower mound, PEDs, no PEDs — whatever the conditions in the game and on the field, first basemen, left fielders, and right fielders have dominated on offense.

Let’s examine more closely this relationship between offensive skill and defensive position — both the historical averages and outlier seasons.

We start with 1914 because that is the earliest season for which we have play-by-play information for every game, courtesy of the good folks at Retrosheet. We need play-by-play information to calculate each batter’s offensive statistics for each season.

Next we look at the weighted runs created-plus (wRC+) for each defensive position, by league, for each season. Why wRC+? It’s a composite statistic that captures a batter’s total offensive output for the year — all the singles, doubles, triples, home runs, strikeouts, walks, stolen bases, and caught stealing — and credits a hitter for how valuable each of those actions was in producing runs.

FanGraphs adjusts the raw numbers to account for the effects of playing in different ballparks and different leagues, and then scales the stats by setting 100 as league average. Pitchers’ batting stats are excluded in calculating the league average.

For example, Stan Musial posted a 166 wRC+ in 1952 — the highest wRC+ in the National League that season. That means he produced 66% more runs than the average National League batter that season (not including pitchers).

To calculate the wRC+ for each defensive position for each season, FanGraphs takes the average of the wRC+ produced by each hitter who played at least 25% of his innings at a position that season. If a player splits his time between two or more defensive positions, his wRC+ for the entire season is included in the wRC+ calculation for both positions. Let’s return to Stan Musial. In 1956, Musial played 873 innings at first base and 441 innings in right field. His 138 wRC+ is included in the wRC+ for National League first baseman and National League right fielders for 1956.

With that background, here’s what the numbers show.

Those poor shortstops. The defensive wizards haven’t produced an above-average wRC+ in either the American League or the National League in the last 101 seasons. Not one time. American League catchers have the same distinction. National League catchers eked just over the average line twice: in 1935, senior circuit catchers posted a just-better-than-average 101 wRC+; and in 1977, Tim McCarver, Gary Carter and Johnny Bench pushed the National League backstops to a robust 103 wRC+.

Second basemen fared slightly better than their double-play partners. American League batters who played the keystone produced a wRC+ over 100 just once, in 1915. But in the National League, second basemen bested the 100 wRC+ mark four times — in 1921, 1924, 1925 and 1927 — thanks largely to Rogers Hornsby. Indeed, Hornsby was so prolific at the plate in 1924 that he carried second basemen to the highest wRC+ of all position players in the National League—the only time second basemen have achieved that distinction since 1914.

With that said, the fact that Hornsby was able to drag his second base brethren above the 100 wRC+ mark four times is a testament not only to his prolific offense, but to the size of the National League in the 1920s. There were only eight teams in the senior circuit until 1962, when two teams were added (New York Mets and Houston Astros). Since then five more teams have joined. Last season, second baseman combined for 12,658 plate appearances. In 1924, that number was just 5,552, so each second baseman had a greater impact on the total wRC+ for that defensive position than a second baseman would today. The same is true for the other positions, prior to 1962, which is why we see greater variation in wRC+ by position on year-by-year basis in the first 50 years of the study.

As feeble as shortstops have consistently been at the plate in the last 100 years, first basemen have been just as consistently productive. Only five times since 1914 did first basemen, as a group, fail to post a better-than-average wRC+ — in the American League, they fell below the 100 wRC+ mark in 1914, 1948 and 1957. National League first basemen also struggled at the plate in 1948, and again in 1949, producing runs at a league-average rate both seasons.

Right fielders are next in line. They beat average run production in all but 11 American League seasons and four National League seasons, with three seasons right at the 100 wRC+ mark. So out of 202 seasons (101 in each league), right fielders produced more runs than league average 184 times. For left fielders, that number drops to 180 — 13 American League seasons and nine National League seasons at or below league average in run production.

That leaves third basemen, center fielders, and designated hitters. Of course, designated hitters don’t play a defensive position — that’s the point, after all — but they do produce runs, so it’s worth exploring how a position dedicated solely to offense has fared against the league average. Pretty well, it turns out: they’ve produced only one season below the league average, in 1993. But in the 42 seasons since the DH was introduced, designated hitters have led the American League in offensive production only six times and shared the lead with either first basemen, left fielders, or right fielders another seven times.

When looking at run production over time, third basemen and center fielders appear as mirror images of each other. Center fielders as a group posted a better than league-average wRC+ all but 48 times in the 202 combined American League and National League seasons, while third basemen bested league-average run production only 53 times.

What’s interesting about those numbers is how strictly they play to type, to the point that the rigidity of the hierarchy appears to be a product of self-selection and design. Talk to any scout, manager, or GM, and you’ll hear that the backbone of a team’s defense is up the middle — catcher to shortstop and second, to center fielder — and the engine of the offense is from the corners at first and third base, and left and right field. That’s what you’ll hear now. That’s what you’ll read about how baseball was played dating back to the turn of the 20th century.

A strong defense up the middle is so integral to success in baseball that it may explain why first basemen, left fielders, and right fielders have consistently outproduced catchers, shortstops, and second basemen at the plate, year in and year out, over the last 100-plus years. Even with all the changes in rules and ballpark design; even with the inclusion of players regardless of race and ethnicity; even with the rise and fall of PEDs and the changes in training, nutrition and fitness; even with the use of sophisticated analytical tools; even with all of that and more, the fundamentals of the game remain the same.

Tory Hernandez worked for the Los Angeles Angels from 2005 to 2011, first as a player-development analyst, then as a scout and later as the manager of baseball operations. I shared the data with him and asked him why he thinks the offensive hierarchy has remained unchanged. “The game of baseball,” Hernandez replied, “is still 90 feet to first base. It’s still 60 feet, 6 inches from the mound to the plate. The outfield dimensions are pretty much the same. Through different eras and different trends, the game is still linear.”

For Hernandez, even if ballplayers today are bigger, faster and stronger than players 100 or even 50 years ago, the game remains structured around a diamond with a limited number of ways to get on base and score runs. In basketball and football, new offensive schemes, shifts in rules, and bigger, stronger players can — and have — transformed the game. Not so in baseball. Just as it did in 1914, every play in baseball in 2014 started with the ball in the pitcher’s hands, with one of a few options to begin the play — pitch to the batter, pitch out to defend against a steal attempt, or throw to a base to keep a runner close or to catch him trying to steal. Those options keep defensive pressure on the infield, particularly the catcher, shortstop and second basemen. The up-the-middle defense.

In 2014, for example, there were 48,148 fielding assists recorded in the majors. Shortstops and second basemen accounted for 27,315 of them, roughly 57%. First basemen and third basemen combined to make 12,244 assists, roughly 25%. Together, all major-league outfielders made 31,017 put outs. Center fielders had the most by far: 12,305, roughly 40% of the total.

But do you still need to sacrifice offense for good defense up the middle? Aren’t we over the days of the scrappy second baseman and lanky shortstop? Shouldn’t this be one of the modernizations made possible by 21st-century athletes? Look at Troy Tulowitzki. Look at Chase Utley. Look at what Barry Larkin and Cal Ripken and Roberto Alomar did on the field and at the plate. When Tory Hernandez looks at those players, he sees once-in-a-generation talent. If there were more Tulowitzkis out there playing professional baseball — or thinking of playing professional baseball — there’d be plenty of teams willing to play those guys at shortstop, instead of pushing them to first base or the outfield.

Brad Kullman agrees. Kullman worked in scouting and player development for the Cincinnati Reds from 1996 to 2006, including a stint as assistant general manager from 2002 to 2006. More recently, he’s worked as a pro scout for the San Diego Padres and Chicago Cubs. “Scouts are always looking for the five-tool player,” Kullman told me. “That’s been consistent over time.” But not all guys have five strong tools and when they don’t, you have to make choices. “There are two things you can’t teach to a ballplayer — running speed and arm strength,” Kullman added. Even with the influx of talent from around the world, there are only so many guys who can play shortstop at the major-league level. If they can post a 125 wRC+, that’s great, but it isn’t a job requirement.

There have been exceptions, of course. Derek Jeter and Hanley Ramirez (when he played shortstop) contributed much more to their teams at the plate than in the field. Likewise, Jeff Kent and Ray Durham were offense-first second basemen most of their careers. But it’s not easy to find a team over the last half century that emphasized offense at every position, no matter the cost on defense.

There is a job requirement for shortstops, second basemen, third basemen, and catchers, one we don’t think about often, but when it’s pointed out (like it was to the author), it’s an aha! moment. Catchers, shortstops, second basemen, and third basemen have to be right-handed or, at the least, throw with their right arm. You can’t throw across your body from the left side of the infield to the right side of the infield with your left arm. Some argue that catchers need not be right-handed but that baseball simply prefers right-handed catchers. Still, there have been no lefty-throwing catchers in baseball in the Retrosheet Era.

How does that affect the offensive hierarchy? Think about all the left-handed players who were offensive powerhouses: Babe Ruth, Barry Bonds, Lou Gehrig, Tris Speaker, Stan Musial, Tony Gwynn, Willie Stargell, Willie McCovey, Rickey Henderson, and Reggie Jackson. All Hall-of-Famers. All outfielders or first basemen (or both). In fact, 21 of the top-50 first basemen in the period from 1914 to 2014, as ranked by WAR, were left-handed. For outfielders, lefties made up 14 of the top 50 by WAR.

While it may be difficult to imagine Barry Bonds, Babe Ruth or Willie McCovey as a second baseman, shortstop, third baseman, or catcher, there have been plenty of left-handed players over the last 100 years with top-notch offensive stats who might have played one of those positions if they’d been right-handed. Guys like Kenny Lofton, Brian Giles, Will Clark, John Olerud, Don Mattingly, Fred McGriff, Wally Joyner, Jacoby Ellsbury, Steve Finley and Shawn Green all had offensive skill sets more commonly found among middle infielders or third baseman, but the essential nature of the diamond and the counter-clockwise path for runners to first, second, third, and home blocked that path for these and many more.

**********

Baseball will continue to innovate. Teams are always looking to exploit a market inefficiency. Extreme shifts are already changing where players are positioned and what they’re asked to do on any given play. The league is looking for ways to make the game more interesting and exciting. This season, we’re getting a glimpse of the breadth of data that will be available from StatCast, MLB’s tracking technology.

Perhaps the future will bring changes to the rigid offensive hierarchy of the last 100-plus years. Until then, don’t expect your team’s catcher, shortstop, second baseman, or third baseman to power the offense.