THE WHEELS FALL OFF: CJ2K and the Predictability of Breakaway Backs Losing Their Burst

The marquee signing of the New York Jets’ 2014 offseason was former Tennessee Titan running back Chris “CJ2K” Johnson, once the undisputed fastest-man in the NFL. Johnson is off to a decent, if unspectacular, start to the 2014 campaign with a 3.9 Yards Per Carry (YPC) average on 51 total carries. However, such performance falls far short of the lofty expectations of some Jets’ fans, who were expecting the former 2,000-yard rusher to revitalize their running game with his dynamic speed and make them a contender. Could this still happen, or is it another case of unrealistically high expectations heaped on a former – and aging – All-Pro with more mystique and aura than speed and ability at this point of his career?

Mike Tanier wrote an interesting piece on how the running back position has become the worst job in sports:

“We can all make a list of running backs who had long careers: Curtis Martin, Emmitt Smith, Marcus Allen, Jerome Bettis, John Riggins and so on. Two things start to happen after we begin listing. 1) We realize we are all listing the same players. 2) We rapidly begin running out of players, even with decades of history to draw from. Those are signs that the lists are actually rather short.

If we do a little research, we also start to notice that some of our “last forever” guys did not last as long as we thought. Franco Harris stopped reaching the Pro Bowl when he turned 30. Eric Dickerson had his last good year when he was 29. Even Bettis stopped cracking 1,000 yards at age 29, settling into a late career as a committee back, short yardage specialist and civic treasure. Allen did roughly the same thing.”

Johnson turned 29 in September and entered the 2014 season with 1,742 total career rushing attempts in his career. The Jets were really his only serious suitor in the free agent market because almost everyone in the NFL knows that running backs are: A) largely fungible; and B) on the downslide after age 25 or 1,500 carries, whichever comes first. Everyone, apparently, except for the Jets.

Only in Johnson’s first two NFL seasons (2008 and 2009) has he averaged more than 4.6 ground yards per carry. In four-plus years since, his rushing output has dropped to 4.2 yards per carry – which happens to be the NFL average during that period.

His six-straight 1,000-yard seasons have more to do with volume than efficiency. Johnson has rushed between 251 and 358 times in every full season he’s played, with a median annual workload of 277.5 carries.

Since 2008 there have been 45 seasons by running backs with at last 277 carries. Of those, how many failed to rush for 1,000 yards? Zero. Zero out of 45.

Over that same span, running backs logged 251 or more carries in a season on 68 occasions. How many failed to crack the 1,000-yard mark? Three out of 68. When those 68 seasons are ranked by rushing yards, Chris Johnson occupies the number 2, 20, 39, 43, 58, and 62 positions on the list. Yes, four of those six years rank in the bottom half.

Sure, some of that is selection bias. Teams generally aren’t inclined to give terrible players 250 or more carries. Still, some of the names on that list with multiple 1,000-yard seasons ‒ Cedric Benson (3), Shonn Greene (2) and Ryan Grant (2) ‒ would hardly be considered NFL rushing stalwarts. Clearly, if a running back gets enough carries, he’s going to get 1,000 yards. Opportunity does not necessarily imply talent or skill. Johnson may well have talent, but his counting totals overstate the value he’s provided throughout his career.

Dynamic Numbers?

“As recently as a year, year and a half ago, this guy was dynamic.”– Marty Mornhinweg, New York Jets offensive coordinator

That quote perfectly sums up both the Jets and what has happened to CJ2K: Namely, his most dangerous asset as a runner ‒ the breakaway speed and elusiveness ‒ has largely disappeared. Consider the following two charts, first from Pro Football Focus:

PFF Grades & Ranking

Year Overall Run Pass Catching Blocking Elusive Breakaway % Pass Block
2009 2.0 (#8) 6.5 (#3) -0.2 (#26) -2.7 (#53) 40.3 (#16) 50.4 (#1) 91.5% (#51)
2010 -9.1 (#53) 3.6 (#7) -5.6 (#57) -7.1 (#58) 38.5 (#19) 42.0 (#5) 89.7% (#51)
2011 -9.9 (#65) -4.8 (#65) -4.8 (#64) 0.2 (#36) 25.1 (#37) 36.9 (#11) 94.3 (#32)
2012 -9.3 (#58) -6.3 (#50) -6.3 (#59) -0.6 (#39) 18.8 (#39) 39.5 (#5) 92.9 (#41)
2013 -3.1 (#42) 1.8 (#33) -2.2 (#43) -3.1 (#47) 15.5 (#47) 25.2 (#23) 92.3 (#35)
2014 -7.0 (#52) -4.9 (#51) -1.9 (#48) -0.2 (#35) 33.9 (#25) 17.5 (#34) n/a

It charts the last six years of PFF grades for Johnson (including five games this year), followed by his rankings among peers (lower numbers are better — includes RBs with at least 25% snaps played).

In terms of PFF’s rushing component, Johnson did bounce back in 2013 (+1.8) following his career-worst season in 2012 (-6.3). However, it still was far, far off from his former glory days ‒ the 2,000 yard season (+6.5) was way back in 2009, a season that began when people still thought Tiger Woods could drive well. The most alarming drop-offs? His breakaway percentage (explained here) and elusiveness rating (defined here), regressed enough (career lows in both data and league ranking for each statistic) to no longer be considered even an average “big play” back among his peers.

Mind you, Johnson was never an outstanding pass-catching back, nor an effective pass blocker. However, to his credit, he improved on both fronts in recent years. Perhaps he knew that his once potent breakaway speed was gone and strived to be more of an all-around back. There’s nothing wrong with that, but what he became last year was a back that doesn’t do anything particularly well:

The graph simply plots his PFF rankings listed above, from 2010 to 2013. The y-axis (far left) indicates his league standing among qualified peers at running back (the lower the data point, the better).

Earlier in his career Johnson was a home run hitter and often mentioned among the better backs in the league, despite his atrocious pass-catching and blocking skills. In 2013, however, his rankings in PFF’s categories ranged from a high of #23 (breakaway %) to #47 (blocking and elusive rankings). That’s not even “good,” much less “elite.” That is the definition of a below-average running back, one with enough accumulated wear and tear to dissuade expectations for substantive improvement in 2014 or beyond. And even taking the small five-game sample into consideration, his numbers so far this season bear that out.

Perhaps the Jets could live with the shorter gains as long as he breaks a couple of big runs. But what happens if Johnson can no longer do the one thing that made him effective while not drastically improving on his other, career-long deficiencies?

Let’s take a quick look at his traditional stats and see if they match up with what we’ve seen from the PFF grades:

Year Att Yds Y/A Y/G A/G T/Scrim
2009 358 2006 5.6 125.4 22.4 2509
2010 316 1364 4.3 85.3 19.8 1609
2011 262 1047 4.0 65.4 16.4 1465
2012 276 1243 4.5 77.7 17.3 1475
2013 279 1077 3.9 67.3 17.4 1422
2014 51 200 3.9 33.3 8.5 240

Like all aging backs, we see a steady downward trend across many categories, including yards per attempt (which last year fell below 4.0 for the first time in his career), yards per game, average attempts per game, and the all-important yards from scrimmage. This season, Johnson isn’t even rushing 10 times per game (barely over half of his 2013 usage), and he’s on pace for just 733 total yards from scrimmage ‒ roughly half of what he averaged the previous three years (1,454). In the Jets’ last three games Johnson had merely 16 rushes, including 3 against Denver for a whopping 9 yards.

There are still more nails to hammer into the coffin, this time from Football Outsiders. Here are their running back rankings for 2013:

At first glance, you may look at the DYAR ranking (which serves as the sorting index for the chart) and see Johnson in the 17th spot. Not too bad, right? Well, not quite.

Take a look at success rate and corresponding ranking, the two columns furthest to the right. This stat (explained here) gauges a running back’s ability to gain a prescribed percentage of needed yardage depending on down-and-distance situations, scoreboard margin, and time remaining. Johnson’s 46% rate places 31st among his peers, while giving him the less-than-desirable label of “volume runner.”

Being a “volume” runner with disappearing speed and elusiveness gives more weight to the contention that his already declining contributions will even be smaller in 2014. Here’s a graph from the RB decline chart mentioned in the Mike Tanner article, to which we’ve added a “CJ2K” line for Johnson (in red):

So far, Johnson has indeed failed to live up to Jets fans’ hopes and dreams. Among the 37 NFL rushers with at least 40 carries through Week 5 (Note: Football Outsiders revises content at that page weekly), he ranked 30th in DYAR (-19), 30th in DVOA (-18.6%), and 33rd in Success Rate (38%).

Playing devil’s advocate, Johnson is not a bad insurance policy against Chris Ivory‘s injury history and Bilal Powell’s ability to be the bell cow through a 16 game season. However, with Johnson being paid a base of $8M plus up to $1M in incentives over two guaranteed years, one would think General Manager John Idzik and Head Coach Rex Ryan would expect more in return. The jury is out on whether Johnson will make that investment worthwhile, but various indicators show he is no longer capable of that, no matter how many pundits and Jets fans wish otherwise.

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