When you think of the fullback in today’s game, you probably think of a player like Vonta Leach , widely regarded as the best blocking back in the NFL. There are also the H-Back/receiving fullback types, like Marcel Reece or James Casey , and the rushing fullbacks like Le’Ron McClain Jacob Hester , and Mike Tolbert . And it’s the fullbacks who double as goal line threats like John Kuhn and Jed Collins who get the most attention from fantasy players. But the fullback position was not always so specialized.

In fact, fullback used to be the glamor spot in the backfield, and that’s the position played by Marion Motley, Dan Towler, Tank Younger, Joe Perry, Alan Ameche, John Henry Johnson, Rick Casares, and the great Jim Brown. Jim Taylor and Paul Hornung both played fullback in Green Bay, while Keith Lincoln and Cookie Gilchrist were great fullbacks in the AFL. In 1966, Minnesota fullback Bill Brown led the NFL in carries. That wasn’t unusual, as fullbacks were key parts of rushing attacks in that decade: the four leading rushers of the ’60s — Jim Brown, Jim Taylor, Don Perkins, and Dick Bass — were all fullbacks. In 1965, fullback Tom Nowatzke went 4th overall in the AFL Draft while Ken Willard (a future four-time Pro Bowler) went second overall in the NFL Draft… just ahead of Dick Butkus and Gale Sayers.

The ’70s were dominated by great fullbacks, as future Super Bowl MVPs Larry Csonka, John Riggins, and Franco Harris were among the game’s best players. And while lacking in star power, Sam Cunningham, Mark van Eeghen, and Pete Johnson were all Pro Bowl-caliber players and key parts of their team’s offenses, too. As the passing game opened up after 1978, the role of the fullback changed. William Andrews was the throwback, but Roger Craig and James Wilder entered the league as fullbacks at a time when the position was evolving into a more specialized role, and had their best seasons after switching to halfback. In Wilder’s case, Tampa Bay switched to a two-tight end offense to get Jerry Bell and Jimmie Giles on the field (and removing running back Mel Carver from the field was an added bonus). For Craig, he played fullback when he was joined in the backfield with Wendell Tyler and Joe Cribbs and halfback when Tom Rathman replaced them.

Thus began the era of the specialized backfield. Seattle’s John L. Williams and later Arizona’s Larry Centers were outstanding pass catchers. The two best teams of the late ’80s/early ’90s had Daryl Johnston and Tom Rathman, fullbacks with solid hands and the ability to run inside, but who made their money as blockers. The fullback remained important in the West Coast Offense, and Green Bay (Edgar Bennett, William Henderson) continued to use a versatile fullback, too. For most of the league, though, the fullback turned into essentially just a blocking back, even if the players who piled up the rushing yards (Mike Alstott) or catches (Richie Anderson) became the more famous players at the position. The unsung heroes were guys like Howard Griffith, Lorenzo Neal, Tony Richardson, and Mack Strong, who achieved job satisfaction by blocking for 1,000-yard rushers.

And now, the fullback is practically extinct. Games go by without a team line up even once in the I-Formation, as the three wide receiver set has replaced more traditional looks. The WCO has been replaced by the spread offense. It’s fair to wonder if in ten years, the fullback will be gone for good: in April’s draft, only three fullbacks were selected — Harvard’s Kyle Juszczyk (pick 130), Kansas State’s Braden Wilson (204), and Wake Forest’s Tommy Bohanon (215). Two of the top rushing teams in the league are using converted defensive players as fullbacks (Bruce Miller in San Francisco and Darrel Young in Washington), while Seattle’s fullback is a former college quarterback (Michael Robinson). It appears the position is being as marginalized as much as possible.

There are several explanations for how the fullback became the NFL’s version of the human appendix. When Cookie Gilchrist and Jim Brown were stars, they were as big and as strong as many of the opposing defensive linemen they faced. The graph below shows the average weight since 1960 for all running backs (this includes halfbacks, tailbacks, and fullbacks) in blue, all linebackers in orange, and all defensive linemen in red:

The increase in the size of defensive linemen has made running up the middle less attractive. And now that passing is more effective than ever — i.e., there are fewer sacks, fewer incomplete passes, and fewer interceptions — a run up the middle is a less useful alternative. The rules changes and innovations in the passing game have essentially resulted in mass layoffs for fullbacks.

What about the blocking fullback? He’s essentially been replaced by the slot receiver. A great blocking fullback will take a linebacker out of the play, but an average slot receiver will take a linebacker off the field. Teams quickly found that running out of a 3-WR/1-TE offense against a nickel defense is easier than running against a base defense when you have both a tight end and fullback in the game. The math in the blocking scheme is the same, but you simply crowd the box by leaving in a fullback while most slot receivers can be capable blockers against a nickel defender. And by placing a wide receiver on the field, teams will be more effective in the passing game, allowing the quarterback to have more options pre-snap.

The fullback could replace the tight end, in theory — a three-wide receiver, two-back offense would still force defenses to play in nickel. But tight ends are now among the most athletic players in the game, and the fullback is essentially a shorter, slower, tight end. Most of the top fullbacks (Leach, Kuhn, Darrel Young, Greg Jones) are all in the six-foot, 250-260 pound range. One exception is Minnesota’s 6’5 Rhett Ellison, although he’s a hybrid tight end/fullback, and the Vikings have a more traditional fullback in Jerome Felton. If you want a fullback to lead block, the shorter player has an advantage by having a lower center of gravity, but in most other situations, teams want the bigger player. You’ll never see the fullback completely eliminated for this reason, but teams aren’t looking to leave a multi-dimensional tight end or a slot receiver off the field for a six-foot lead blocker.

Could the fullback as pass catcher model be revived? Larry Centers caught 200 passes in 1995 and 1996 while Richie Anderson caught 88 passes in 2000. But those teams rarely used slot receivers, and offenses that revolved around the fullback did so more out of necessity than design. No offensive coordinator is spending his time thinking about how he can get the ball into the hands of his fullback more often.

From an evolutionary perspective, the 15-year-old high school football player isn’t thinking that playing fullback is his ticket to the NFL. A fast fullback becomes a running back, a tall fullback becomes a tight end, and a strong fullback puts on weight to become a linebacker. From an athletic standpoint, it seems that fullback is now the position choice of last resort.