Every offseason we hear it: Such and such running back had a high yards-per-carry average as a backup, and, now that they have a full-time role, they will be a fantasy superstar.
It was the argument that put the helium in David Wilson’s fantasy balloon last season and so many more players before him.
Frankly, the argument is nonsense.
The difference between running the ball in passing situations and running the ball when the defense knows you are running the ball is night and day. As such, very average running backs can be surprisingly successful in a backup or third-down role.
Since 2003, 39 running backs have averaged over five yards a carry as primarily backup runners. 26 of those backs were given an opportunity to start a significant amount of games at some point in their career. On average, those 26 players lost 1.25 yards per carry from their backup to their starting season.
That isn't to say some of the backs were not successful. Michael Turner and Steven Jackson more had successful transitions from backup to starter, but even those success stories saw a significant decrease in their per-play numbers as starters.
The only player over the last decade that has maintained a gaudy YPC when stepping into the starting role is Jamaal Charles. He is a special player and a great exception that proves the rule. Getting more carries almost universally leads to a decrease in per-play numbers.
This is important to keep in mind as we look at two of the bigger backup-to-starter transitions in free agency this year.
Now that it is official, the focus turns to what Ben Tate will do in Cleveland.
The difference between Tate and some of the other backup-to-starter backs we've seen in the past is Tate has a decent track record as a starter.
Tate has started nine games in his career and played the majority of snaps in 11 games. In those 11 where he saw extensive action, Tate posted a 205-900-5 line. His 4.4 yards per carry in those games is a full .3 lower than his career average, but still a solid number.
When looking at his numbers, though, we also have to consider several factors. The first is the offensive line.
Tate is moving from a perennial, top-ten run blocking line to an offensive line that struggled to open holes last season and has not added anyone substantial this offseason. One could argue the departure of RG Shawn Lauvao was addition by subtraction, but there is not a huge reason to believe the Cleveland offensive line will improve dramatically in 2014.
There is also a question of how involved Tate will be in the passing game.
He did catch a solid 32 passes last season, but his 4.1 yards per reception was the worst in the league among qualifying players. The next closest player was Ray Rice at 5.5 yards per reception.
More worryingly, Kyle Shanahan is the new offensive coordinator in Cleveland. He has a history of rushing success and may well be able to fix what ails the Cleveland offensive line, but his lead backs have traditionally been underutilized in the passing game. Alfred Morris has only 20 receptions over the last two seasons combined.
Shanahan has used backs out of the backfield before – Steve Slaton registered some 40+ catch seasons under him in Houston – but the younger Shanny has proven time and again he is not going to ask a player to catch the ball out of the backfield if they are not good at it. Tate might not be good at it.
The situation in Cleveland, then, is not as great as it seems, and Tate is the not the special talent that can overcome a mediocre situation. It is very unlikely Tate pulls out a Jamaal Charles or even an Eddie Lacy season in Cleveland. He ceiling is just not that high.
Normally that would not be a problem, but Tate’s floor makes that lack of potential very worrying.
Tate’s injury history has been discussed to death, but it is for good reason. He has two I.R. stints in four years and has been hampered by injuries in each of the last two seasons.
If he cannot stay healthy in a backup role, it is hard to see him suddenly carving out a 300-touch season as a starter, and that is most likely what it would take to propel Tate into the RB1 stratosphere.
Tate has a limited ceiling and a cavernous floor. That is the type of player to avoid in fantasy, especially considering the effect his name will have on his ADP.
The other big backup-to-starter free agent was Toby Gerhart.
The Jaguars shocked the world by giving career backup Gerhart $10.5 million over three years, including $4.5 million in guaranteed money on the first day of free agency.
The deal almost assures Gerhart will be the lead back next season in Jacksonville, and that reality leads to a very important question. How effective will Gerhart be in that role?
Uninspiring was the first word that came to mind. Everything Gerhart has ever put on tape screams plodder that gets what is blocked and not much else. As many people kindly pointed out on Twitter, however, Gerhart’s career per-play numbers are actually impressive.
Gerhart sports an excellent 4.7 average on 276 career carries and has 1,905 total yards with eight touchdowns in only 353 career touches.
Using those numbers alone, it is not crazy to project Gerhart for 1,400 total yards and six total touchdowns in a full-time role. That would make him top-end RB2 and worthy of a pick early in the third round.
The problem is those numbers are horribly misleading.
The majority of Gerhart's career carries came behind a top-five run blocking offensive line. From 2010 to 2013, the Vikings finished third, first, and sixth in ProFootballFocus’ run blocking rankings. Jacksonville, on the other hand, ranked dead last in run blocking last season, and it was not particularly close.
The Jags have signed overrated guard Zane Beadles and should address the position further in the draft, but even a substantial improvement in run blocking would only be good enough to vault them into the middle third of the league.
There is a more important reason than blocking to doubt Gerhart’s per-play numbers, though.
Gerhart spent almost his entire career as a third-down, situational running back in Minnesota, meaning a disproportionate amount of his 276 career carries have come on third down or second and long. These are traditionally passing situations that afford a running back larger running lanes than they get in more traditional running situations.
To see how he might fare as a starter, it is important to pick out games in which Gerhart actually filled that role.
Gerhart played at least half the Vikings' offensive snaps in seven games over his four years with the team. In those games, Gerhart had 132 carries for 552 yards and three touchdowns. That 4.18 yards per carry average is considerably lower than his 4.7 YPC overall and much more in line with the skill set Gerhart has displayed on tape.
In context, then, it is fairly easy to see his 4.7 career YPC is not indicative of his ability as a ball carrier. He is much closer to a four-yard-per-carry plodder, and that makes him nothing more than a RB3 with very little upside in Jacksonville’s underwhelming offense.