In May, I discussed how and why the fullback was being slowly phased out of the game. Some of the main reasons are:

The increase in the size of defensive linemen has made running up the middle less attractive.

The blocking fullback has been replaced by the slot receiver: A great blocking fullback will take a linebacker out of the play, but an average slot receiver will take a linebacker off the field.

Tight ends are now among the most athletic players in the game, and the fullback is essentially a shorter, slower, tight end. Teams aren’t looking to leave a multi-dimensional tight end or a slot receiver off the field for a six-foot lead blocker.

The pass-catching fullback is the option of last resort for an offense, not an element of design. No offensive coordinator is spending his time thinking about how he can get the ball into the hands of his fullback more often.

Fullbacks are being diverted into other career paths: a fast high school fullback becomes a running back, a tall fullback becomes a tight end, and a strong fullback puts on weight to become a linebacker.

But enough about theory: let’s analyze how teams are using fullbacks in today’s NFL, courtesy of Pro Football Focus. Let’s break the teams down into tiers:

Fullbacks need not apply: Arizona, Philadelphia, Denver, Dallas, Detroit, Cincinnati, and Miami

The Cardinals and Eagles have not had a fullback on the field this season. Philadelphia runs a lot of three-wide receivers sets with DeSean Jackson, Riley Cooper, and Jason Avant, and LeSean McCoy and/or Bryce Brown are always on the field. Add tight ends Brent Celek and Zach Ertz see significant playing time, too. You could classify James Casey as a fullback (PFF labels him a tight end), but he has just 60 snaps this year. For Arizona, tight ends Jim Dray, Rob Housler, Kory Sperry, Jake Ballard, and even D.C. Jefferson get on the field in lieu of any fullbacks. Head coach Bruce Arians does not see much of a need for a fullback, as Robert Hughes had just 28 snaps in Indianapolis last year.

Dallas, Denver, and Detroit all use 3-WR/1-TE as their base personnel, and little changes even when those teams are leading. Dallas will put TEs James Hanna and Gavin Escobar on the field with Jason Witten in run-heavy sets, and backup linebacker Kyle Bosworth is responsible for all 9 snaps taking by a Cowboys fullback this year. Wes Welker and Julius Thomas are textbook examples of why the fullback is becoming extinct. Welker’s prowess as a slot receiver far exceeds the value any fullback could add, while Thomas is the type of athletic superfreak teams are finding to play at tight end. Virgil Green, Joel Dreessen, and Jacob Tamme see time when the Broncos want to run, and defensive tackle Mitch Unrein (8 snaps) is the only fullback Denver has used. For the Lions, Joseph Fauria (and, prior to his release, Tony Scheffler) is used when the Lions want more blockers on the field, and the team will occasionally put Reggie Bush and Joique Bell on the field together, too, leaving just two snaps this season for fullback Montell Owens.

On Hard Knocks, the fullback battle between John Conner and Orson Charles received a lot of publicity, but the Bengals simply don’t use a fullback. Charles won that battle, but he’s been on the field for just 24 obvious run snaps this year (he run blocked on 22 of them). The team has so much faith in his blocking that defensive linemen Domata Peko has played fullback on seven snaps this year. Cincinnati is a pure 2-TE team, as both Jermaine Gresham and Tyler Eifert have each logged over 500 snaps. That leaves just one spot left after accounting for A.J. Green and the running back, and that spot is going to Mohamed Sanu or Marvin Jones, not a fullback.

Charles Clay entered the league as a fullback, but he’s Miami’s number one tight end now. With Dustin Keller out for the season, Clay has 531 snaps this year, a couple hundred more than backups Dion Sims and Michael Egnew have combined. That left Tyler Clutts as the team’s fullback, but he was released after the fourth week of the season. Clay can obviously chip in when necessary, but the Dolphins don’t carry a pure fullback. Under Joe Philbin, the Dolphins use the 3-WR set as their base formation, and bring in Sims or Egnew when the team needs some additional beef up front.

The fullback heavy hitters: Carolina, Oakland, and San Francisco

Mike Tolbert is more than just an oversized running back who fits in well in the Panthers offense. Carolina’s offense under Cam Newton is a throwback to the Million Dollar Backfield of a half century ago, and Tolbert is a versatile player who spends about 25% of his time run blocking, 25% pass blocking, and one-third of his time running routes, leaving him to run the ball on about one-sixth of his snaps. Carolina is so starved for wide receivers that backup fullback Richie Brockel has more playing time than all but three Panthers receivers.

Both Bay area teams have mobile quarterbacks and vacancy signs doubling as wide receivers, leading to more time for the fullback. In San Francisco, only Anquan Boldin, Frank Gore, and Vernon Davis have seen more offensive snaps than Bruce Miller among skill-position players. Miller isn’t a runner, but he’s a punishing lead blocker, adding pain to confusion for linebackers trying to determine if Gore or Colin Kaepernick has the ball.

For Oakland, Marcel Reece is of a different species than Tolbert or Miller: he’s more like the Richie Anderson/Larry Centers type, and just over half of his snaps are spent running pass routes. But the Raiders also use Jamize Olawale (78 run-blocking snaps) when the goal is to keep defenders from injuring Darren McFadden for as long as possible.

The situational fullback: New Orleans, New York (Jets), Minnesota, Tampa Bay, Indianapolis, Kansas City, Houston, Seattle, and Jacksonville

You wouldn’t think of the Saints as a fullback heavy team, but Jed Collins has been a regular member of the rotation for years. He’s mostly used as a run blocker, although New Orleans will often substitute Collins for a backup tight end (John Gilmore, Dave Thomas, or Ben Watson, depending on the year), too.

The Jets run a hybrid ground-and-pound/running-is-for-chumps offense under Rex Ryan and Marty Mornhinweg, and fullback Tommy Bohanon (fifth in the league with 270 snaps) appeals to both masters. Ryan loves well, everything about fullbacks, while Mornhinweg used Cory Schlesinger to similar effect in Detroit. Perhaps most importantly, the team has little choice but to put Bohanon on the field consider that the Jets top five wide receivers/tight ends have all missed time.

In 2012, Jerome Felton and Rhett Ellison saw significant action in the Vikings run-heavy offense. Both are seeing less time this year, as Adrian Peterson isn’t running for 2,000 yards and Minnesota is often trailing. In other words, the game scripts have cut into the snap counts for both players, and tight end John Carlson is seeing more playing time, too.

The Schiano Buccaneers seem like the type of team that would try to put a fullback on the field 110% of the time, and the lack of a legitimate tight end or depth at receiver would seem to only reinforce that philosophy. But fullback Erik Lorig has seen a modest 234 snaps (with 166 as a run-blocker), although he would probably get more playing time if he was producing (Lorig has a -5.2 PFF grade). Backup Spencer Larsen also gets in the game when Tampa Bay wants to announce its intentions: he’s run blocked on 21 of the 23 snaps he’s seen the field.

Indianapolis is the head-scratcher here, as Pep Hamilton seems anxious to turn Andrew Luck into a caretaker on a power-running team. Stanley Havili has taken 249 snaps, although that number would likely be lower if Dwayne Allen had stayed healthy. Havili isn’t much of a run-blocker, so his biggest value-add is that his presence often tricks defenses into expecting run. Luck has been excellent on play-action passes this year: according to NFLGSIS, the Colts have averaged 8.00 yards per pass with Havili on the field compared to 6.30 Y/A without him (while averaging 4.44 yards per carry without Havili and 3.78 yards per carry with him).

Kansas City is a run-heavy team with a great defense and a strong game script, so it’s no surprise to see the Chiefs mix in the fullback. Of course, Andy Reid is still the coach, so the snap count must be limited: Anthony Sherman has taken 258 offensive snaps this year, mostly as a run blocker, but that still lags behind tight ends Sean McGrath (398) and Anthony Fasano (378). One might argue that those numbers should be reversed, as Sherman is PFF’s top blocking fullback of 2013.

In Houston, 32-year-old Greg Jones plays a similar role despite spending nine years in Jacksonville as a running back/fullback hybrid. He’ll always be remembered in my eyes for this punishing hit he delivered at Florida State, but Jones has carved out a solid NFL career, too. The Texans run a lot of two-tight end sets with Garrett Graham and Owen Daniels, so most of Jones’ 217 snaps are devoting to run blocking.

You might think Seattle would be a heavy fullback user, but the power-running Seahawks only occasionally bring in the fullback. That player was Michael Robinson last year (335 snaps, 230 run-blocking), but Derrick Coleman handled that role early in the year after Seattle released Robinson (who was dealing with an illness and unable to play). Robinson is back, but Seattle uses three-WR sets more often than you’d think. Even for a team playing with the lead as often as the Seahawks, the fullback (118 snaps for Coleman) is just not a key cog of the offense.

The Jaguars lie on the other end of the game scripts spectrum, but Will Ta’ufo’ou has still seen 190 snaps this year. Who knows how much of that is out of necessity — either to help the poor offensive line or because Jacksonville doesn’t have enough good WRs/TEs to keep him off the field — but Ta’ufo’ou been used as a run-blocker on over half his snaps.

The popular fullbacks: Washington, Baltimore, Green Bay, and Cleveland

Washington’s Darrel Young was drafted as a linebacker out of Villanova, but he’s a full-time fullback now. In the team’s come-from-behind win against San Diego, Young rushed for three touchdowns. The fullback was a big part of Mike Shanahan’s system in Denver (Howard Griffith was a Pro Bowl-caliber fullback in front of Terrell Davis), but Washington has too many playmakers at WR and TE to give too many snaps to a fullback. Pierre Garcon, Leonard Hankerson, Santana Moss, and Josh Morgan all have more snaps than Young, while Logan Paulsen and Jordan Reed have combined for nearly 800 snaps, too. Even third- and fourth- string TEs Niles Paul and Fred Davis have combined for more snaps than Young, which shows that even Shanahan now tends to put the fullback on the field only when he has no other option.

Baltimore’s Vonta Leach is probably the most famous fullback in football, and he starred as Arian Foster‘s lead blocker in Houston under Shanahan disciple Gary Kubiak. But Leach is having his worst season (-7.3 run-block rating) and may be out of the league soon. Baltimore drafted H-back/FB Kyle Juszczyk, but he’s only been on the field for four snaps this season. The Dennis Pitta injury combined with the lack of any consistent play at WR behind Torrey Smith has allowed Leach to see 185 snaps, but he’s part of the problem and not the solution to the Ravens’ running game woes.

If Leach isn’t the most popular name in the game, then that honor falls to Green Bay’s John Kuhn. The popular Packer scored 6 touchdowns in 2010 and then made the Pro Bowl when he matched that feat in 2011. According to NFLGSIS’s Net Yards over Average metric, Kuhn leads the league at 198 yards over average when he’s on the field. He’s an effective lead blocker and does a good job in pass protection, which helps cover for an often shaky line. But we shouldn’t get carried away with the praise, because there’s a reason the Packers have limited him to just 172 snaps. That’s because Jordy Nelson, James Jones, Jarrett Boykin, Randall Cobb, and Myles White have combined for 1,870 snaps, and the Packers are more interested in getting those players on the field. Green Bay averages 2.7 WRs on the field per snap; with a tight end and a running back almost always on the field, that leaves precious few snaps for Kuhn.

Cleveland’s Chris Ogbonnaya is a throwback to yesteryear, when the line was blurred between fullback and tailback. The Browns aren’t a base-3WR team, but Rob Chudzinski is a former tight ends coach and likes to get both Jordan Cameron and Gary Barnidge on the field. “Silent G” actually leads all Browns backs in snaps, but he’s not your run-blocking fullback type. He’s a strong runner, a solid pass blocker and a capable pass receiver, but he’s also the type of player that teams figure out how to upgrade after the season is over. Ogbonnaya is the only fullback on the roster, although Willis McGahee and Fozzy Whittaker are the team’s only other backs.

The Lip Service Crew: New England, New York (Giants), Pittsburgh, Buffalo, Chicago, Tennessee, Atlanta, San Diego, and St. Louis

You probably don’t know who James Develin is, but he’s taken 170 snaps for the Patriots this year. Once Sammy Morris left, Bill Belichick wrote the fullback out of the playbook, but circumstances have enabled Develin to have a role with the team. Those circumstances would be Aaron Hernandez, Rob Gronkowski, Danny Woodhead, Wes Welker (and then his replacement, Danny Amendola), and Brandon Lloyd being off the roster or out of the lineup for long stretches in 2013. Develin is a pure run-blocking back from Brown, and while his PFF grades are not great, the Patriots may not be done with him. Even with Gronkowski and Amendola healthy, Develin was still in on 19 of the team’s 72 snaps against Carolina.

The Giants backfield is always a tragicomedy, and 2013 is no different: six different Giants running backs have between 104 and 141 snaps this season. Read that sentence again, but laugh this time instead of cry. Former Jet John Conner has seen 130 of those snaps, with the overwhelming majority coming as a run blocker. He never was quite as good as Tony Richardson in New York, and eventually fell out of favor with Rex Ryan, but Conner is quietly having a nice season in spot duty with the Giants.

The Steelers have rotated five different halfbacks this year, but the generically named Will Johnson is the team’s lone fullback. Pittsburgh alternates between Johnson and backup tight ends David Paulson and David Johnson when they go heavy, but none of them have been very effective. In other words, Dan Kreider isn’t walking through that door.

Frank Summers is another fossil in the lead-blocker bin, and he’s seen the field on 19% of all Bills offensive snaps. Buffalo is a base-3WR team with Robert Woods, T.J. Graham, and Steve Johnson being complemented by C.J. Spiller or Fred Jackson and TE Scott Chandler. Buffalo drafted WR Marquise Goodwin and TE Chris Gragg in 2013, so expect to see more 4-WR and 2-TE sets in 2014. Both of which will mean a run to the unemployment line for Summers.

You might think new-age, pass-happy Marc Trestman wouldn’t roster a one-dimensional blocking back, but Tony Fiammetta has been on the field for 21% of Chicago’s snaps, with the majority coming as a run blocker. On the other hand, Fiammetta may be being phased out: after 23+ snaps in three of the first six games, he hasn’t seen more than 12 snaps in any of the the Bears’ last four games. The main men stealing his spot on the field are the backup wide receivers, Earl Bennett and Marquess Wilson.

You might assume that Tennessee as an embassy where modern ideas may not enter after the team devoted so many resources to rostering Chris Johnson, Shonn Greene, Chance Warmack, and Andy Levitre. But fullback Collin Mooney – despite having a +9.4 PFF grade –has only been on the field for 18% of the Titans’ offensive snaps. The Kenny Britt implosion hasn’t stopped the Titans from averaging 2.42 WRs per snap, and the tight end trio of Delanie Walker, Craig Stevens, and Taylor Thompson are averaging 1.4 spots per snap. That leaves little room for the fullback other than in obvious running situations.

In Atlanta, Patrick DiMarco and Bradie Ewing have combined for 110 snaps for the team with the fewest rushing attempts this season. The Falcons are another base-3WR team, and will occasionally put Jason Snelling on the field with one of the other halfbacks. Ewing went on injured reserve with a separated shoulder after week two, leaving DiMarco — who is a lead blocker and little else — as the team’s only fullback.

San Diego’s Le’Ron McClain could make the popular list, but he’s being used as a road-grader and little more. The Chargers are a base-3WR team that often brings in either John Phillips or Ladarius Green (both of whom have more snaps than McClain) to join Antonio Gates, leaving little room for the former Raven. Mike McCoy’s offense doesn’t call for a fullback except in obvious running situations, which unfortunately for players like McClain, makes it hard to find a job these days.

Cory Harkey is a tight end/fullback hybrid whose increasing role has coincided with the Zac Stacy era in St. Louis. At 6’4, he’s not going to remind Jeff Fisher of Lorenzo Neal, but he may be a favorite of Brian Schottenheimer. With Jared Cook and Lance Kendricks filling the role of tight ends who can’t run block, Harkey takes their place in run-friendly situations.