Posted by ESPN.com's Mike Sando
We hear players and coaches talk about numbers games at various positions, but we don't always know specifically what they mean.
That's one reason I started tracking roster information in detail. Rosters provide predictive information that goes wasted unless gathered and harnessed with an eye for the big picture.
For this chart, I counted how many running backs each NFC West team kept on its opening-day rosters from 2003 through last season. Arizona kept five last season, five in 2006, six in 2005 and so on. The numbers allow us to generate averages. The bottom row shows how many running back each team is carrying today.
We now have a better idea how many running backs are on the bubble for each team.
Seattle is the only NFC West team entering camp without a declared starter at running back, although Julius Jones has declared himself ready to carry the load. I expect Jones to start and share time with Maurice Morris. The question for Seattle is whether the Seahawks truly have a gifted runner. Jones and Morris are more versatile than Shaun Alexander, but can the Seahawks scare defenses in the running game? We'll know more when Seattle puts on the pads.
The 49ers are carrying six running backs. That is a low number. Mike Martz likes to throw the ball, yes, but his Lions kept six running backs on their opening-day roster last season (Kevin Jones was inactive). The 49ers have flexibility at fullback because tight ends Vernon Davis and Delanie Walker can help at the position.
The Rams used tight end Randy McMichael in an offset-I backfield last season. They even released starting fullback Madison Hedgecock, who signed with the Giants and won a Super Bowl. The Rams have added former Steelers fullback Dan Kreider heading into camp.
The Cardinals have yet to identify a clear successor to Edgerrin James. James and Marcel Shipp turn 30 next month. Arizona drafted Tim Hightower in the fifth round of the 2008 draft, a bit later than some thought the Cardinals would address the position. James is confident his conditioning regimen will prevent the type of physical decline that hit other runners, including A
lexander, as their 30th birthdays passed.