In the pre-season, I wrote three pieces on Cleveland Browns rookie Trent Richardson.  As part of a thought experiment, I wondered who would lead the NFL in rushing yards from 2012 to 2021? I narrowed my finalists to LeSean McCoy, Beanie Wells (was I drunk?), DeMarco Murray (ouch), Richardson and the rest of the rookies, and then a few college running backs. I concluded that Richardson was the obvious frontrunner, with McCoy, Doug Martin, and Marcus Lattimore (double ouch) as the next best bets. I’m not really sure 2012 helped clarify the issue, although Martin and Alfred Morris certainly raised their chances.

Then in August, I looked at the production of the highest drafted running back in each draft class.  I discovered that slightly fewer than half of the highest drafted running backs led their class ^[1]Note that this only includes drafted running backs. in rushing yards as a rookie; as you can see, “the field” also turned out to be a better bet than Richardson in 2012:

In that post, I also noted that the running back drafted first in his class was slightly less successful over the course of his career: only one-third of the highest-drafted running backs finished with the most career rushing yards in their class.

The final post on the topic ended up being more relevant to Alfred Morris than Richardson. In August, I compared how the top rookie running back performed over the rest of his career relative to the other members of his class. From 1992 to 2002, 10 of the 11 backs to lead their class in rushing yards as rookies ended up finishing with the most career rushing yards. But in recent years, that trend has reversed itself: the odds are long that Ben Tate (2011), LeGarrette Blount (2010), Knowshon Moreno (2009 and competing with Arian Foster and LeSean McCoy), or Steve Slaton (2008) will also finish with the best careers from their class.

So where do we stand on Richardson and Morris? A year later, how much credit do we give Richardson for having been the #3 pick in the draft? For Morris, how much do we downgrade him for being a 6th round pick? And how does the presence of Robert Griffin III complicate things?

On average, we expect the 3rd pick in the draft to produce about 34 points of Approximate Value, while Morris’ 173rd slot is expected to add only two points of career AV. But we don’t need AV to compare running backs to each other.

Instead, let’s look at the 20-year period from 1988 to 2007. Over that time frame, there were 23 running backs selected in the top 10 of the draft, with 14 of them being chosen in the top five. The table below shows how many rushing yards those 23 running backs gained during their rookie season (on the X-Axis) and over the first five years of their career (on the Y-Axis). The top five picks are in blue, while the other top-ten selections are in red. The first four letters of each player’s last name and first two letter of their first name are next to the data point.

As you can see, there’s a pretty clear relationship between rookie production and how that player fared over the long-term. I suspect that’s because top-ten running backs are given ample opportunity to succeed, and running back is perhaps the easiest position for a rookie to excel; the learning curve is not great (at least when it comes to running), so if you don’t show it early on, odds are you don’t have elite ability. Adrian Peterson, LaDainian Tomlinson, Barry Sanders, Edgerrin James, Jerome Bettis, Marshall Faulk and Fred Taylor all topped the 1200-yard mark, and all turned into very good-to-Hall of Fame caliber players. ^[2]Of course, year one can be a big component of through-five-years-production, so that probably explains some part of the correlation.

For the most part, the “busts as rookies” group tended to underperform, although players like Garrison Hearst, Cedric Benson, and Thomas Jones did experience late-career success with other teams. The black dotted line running vertically from the 950-yard mark shows where Trent Richardson will one day be placed. I think a player like Ricky Williams is a good comparison for many reasons, although that would appear to be the optimistic projection for him over the next four years. I’m not pessimistic on Richardson’s outlook, but I think the noncontroversial position is his career outlook looks slightly less rosy now than it did a year ago.

What about Morris? As you might imagine, it’s not easy finding comparisons. From 1988 to 2007, only two running backs drafted after pick 150 gained 1,000 yards as a rookie: Terrell Davis and Mike Anderson. It doesn’t take a genius to figure out what those two backs have in common with Morris, either. For all his faults, Mike Shanahan has achieved unparalleled success with lowly-regarded running backs. If we drop the cut-off to pick 125, we add one more running back: Olandis Gary.

By adding undrafted running backs, we finally get a non-Shanahan player: Dominic Rhodes. The Broncos running backs tended to perform well whenever healthy, while Rhodes tore his ACL after his rookie season and was never the same player. That makes it doubly hard to get a read on Morris, especially since he didn’t just cross the 1,000-yard mark, he obliterated it. In fact, he joined Eric Dickerson, George Rogers, and Ottis Anderson as the only players to rush for 1,600 yards as a rookie. That’s because Morris averaged 4.8 yards per carry, an excellent figure (although likely aided by playing alongside Griffin) that looks even more impressive compared to Richardson’s pedestrian average.

The table below shows all 42 running backs since the merger to record 250 carries as rookie. The columns display each player’s team, number of games, rushes, rushing yards, rushing touchdowns and yards per carry as a rookie, along with his draft pick and draft pick value (necessary to run a regression due to the non-linear value associated with draft picks), and the player’s number of games and rushing yards per game in his sophomore season.

Year	Name	Tm	G	Rsh	RshYd	RshTD	YPC	Pick	PkVal	N+1 g	N+1 ypg
2002	Clinton Portis	den	16	273	1508	15	5.5	51	12.9	13	122
1989	Barry Sanders	det	15	280	1470	14	5.3	3	34.2	16	82
2000	Mike Anderson	den	16	297	1487	15	5	189	1.5	16	42
2008	Chris Johnson	oti	15	251	1228	9	4.9	24	19.9	16	125
1993	Jerome Bettis	ram	16	294	1429	7	4.9	10	26.9	16	64
1979	Ottis Anderson	crd	16	331	1605	8	4.8	8	28.4	16	85
2012	Alfred Morris	was	16	335	1613	13	4.8	173	2.2		0
1978	Earl Campbell	oti	15	302	1450	13	4.8	1	39.6	16	106
2008	Steve Slaton	htx	16	268	1282	9	4.8	89	7.8	11	40
1986	Rueben Mayes	nor	16	286	1353	8	4.7	57	11.9	12	76
1983	Eric Dickerson	ram	16	390	1808	18	4.6	2	36.3	16	132
1998	Fred Taylor	jax	15	264	1223	14	4.6	9	27.6	10	73
2012	Doug Martin	tam	16	319	1454	11	4.6	31	17.6		0
1981	George Rogers	nor	16	378	1674	13	4.4	1	39.6	6	89
2000	Jamal Lewis	rav	16	309	1364	6	4.4	5	31.4		0
1983	Curt Warner	sea	16	335	1449	13	4.3	3	34.2	1	40
2001	Anthony Thomas	chi	14	278	1183	7	4.3	38	15.7	12	60
1999	Edgerrin James	clt	16	369	1553	13	4.2	4	32.6	16	107
1999	Olandis Gary	den	12	276	1159	7	4.2	127	4.8	1	80
1984	Greg Bell	buf	16	262	1100	7	4.2	26	19.2	16	55
1980	Billy Sims	det	16	313	1303	13	4.2	1	39.6	14	103
1996	Eddie George	oti	16	335	1368	8	4.1	14	24.4	16	87
1994	Marshall Faulk	clt	16	314	1282	11	4.1	2	36.3	16	67
2005	Cadillac Williams	tam	14	290	1178	6	4.1	5	31.4	14	57
1995	Curtis Martin	nwe	16	368	1487	14	4	74	9.4	16	72
2007	Marshawn Lynch	buf	13	280	1115	7	4	12	25.6	15	69
2004	Willis McGahee	buf	16	284	1128	13	4	23	20.3	16	78
1988	John Stephens	nwe	16	297	1168	4	3.9	17	22.8	14	60
2008	Matt Forte	chi	16	316	1238	8	3.9	44	14.3	16	58
1989	Bobby Humphrey	den	16	294	1151	7	3.9		0	15	80
1973	Boobie Clark	cin	14	254	988	8	3.9	302	0.1	8	39
1980	Joe Cribbs	buf	16	306	1185	11	3.9	29	18.2	15	73
1993	Ronald Moore	crd	16	263	1018	9	3.9	87	8	16	49
1998	Robert Edwards	nwe	16	291	1115	9	3.8	18	22.3		0
1995	Rodney Thomas	oti	16	251	947	5	3.8	89	7.8	16	9
2001	LaDainian Tomlinson	sdg	16	339	1236	10	3.6	5	31.4	16	105
1996	Karim Abdul-Jabbar	mia	16	307	1116	11	3.6	80	8.7	16	56
1995	Rashaan Salaam	chi	16	296	1074	10	3.6	21	21	12	41
1991	Leonard Russell	nwe	16	266	959	4	3.6	14	24.4	11	35
1994	Errict Rhett	tam	16	284	1011	7	3.6	34	16.7	16	75
2012	Trent Richardson	cle	15	267	950	11	3.6	3	34.2		0
1999	Ricky Williams	nor	12	253	884	2	3.5	5	31.4	10	100

Now let’s exclude Morris, Martin, and Richardson, along with Jamal Lewis, Robert Edwards, Curt Warner, Olandis Gary, and George Rogers (due to injury) and Bobby Humphrey (due to being a supplemental pick); that leaves us with 33 running backs. What’s interesting is that the correlation coefficient between the rookie YPC average and rushing yards per game average as sophomores is only 0.37, while the CC between the player’s draft value and rushing yards per game average as sophomores is 0.57. The sample size is not all that large, but essentially this indicates that — among all running backs with 250 carries as rookies — draft value still is a larger indicator of future production than rookie yards per rush average.

If we run a regression using draft value and rookie yards per carry as inputs and sophomore rushing yards per game as the output, we get:

Sophomore Rushing Yards per Game = -32.2 + 17.6*YPC + 1.42*DraftValue

What’s that mean for the three 2012 rookies with 250 carries last year?

This is nowhere near dispositive, but it does indicate that Richardson’s draft value still matters. Obviously history also suggests not to bet against a Shanahan running back (unless, of course, the Redskins draft another runner this year), but essentially this regression tells us this: LaDainian Tomlinson (3.6 YPC as a rookie) and Ricky Williams (3.5 YPC) were top-five picks who had unimpressive yards per carry averages in their first year but then rushed for 100 yards a game as sophomores. Meanwhile, players like Steve Slaton and Mike Anderson went from lowly drafted players to rookie with high yards-per-carry averages to sophomore disappointments. In Anderson’s case he had to split carries with Terrell Davis, but Slaton was an outright disappointment. With so few running backs to examine, the regression basically says “whoa, let’s not write off Richardson yet — he could be the next Tomlinson or Williams and he’s not that far off from being the next Edgerrin James.”

I’ll admit to not having a great feel on either of these running backs. And, of course, Doug Martin slots in nicely in the middle, having a better rookie year than Richardson and a higher draft status than Morris. As always, each player is unique, and not a equal-parts amalgamation of prior running backs with similar biographies. I’m tempted to take the optimistic view on how the careers of all three will work out. Richardson was too talented in college and did enough as a rookie to avoid being downgraded too significantly, Morris seems likely to be the next in a long line of Shanahan stars, and Martin has few blemishes. What do you think?