That may be the case with Darren Sproles, who banked nearly $14 million over the last two seasons while serving as a third-down back and kick returner.
Here's the problem with Sproles: He is a one-trick pony whose only elite skill is his ability to catch passes out of the backfield and make plays in space.
He is not effective as a runner. He lacks the patience to let plays develop and the size to break tackles. His career per-carry average of 4.6 yards is inflated due to the number of yards he gains on draws and delays during two-minute situations.
RB Darren Sproles
Where Sproles shines is as a pass-catcher out of the backfield. Despite the fact that opponents yell, "Screen! Screen!" every time he comes out of the huddle, Sproles consistently creates mismatches and finds ways to catch the ball. He caught more than 100 passes over the last two seasons and averaged almost 10 yards on those receptions.
The question facing the Chargers is this: how much do you pay a player whose only elite skill is catching passes out of the backfield? There are other teams out there who will offer Sproles a chance at more touches, and as a result, more money. San Diego can hope Sproles takes a home-team discount, but still the numbers may be tough to align.
There are reasons for the Chargers to push to re-sign their fourth-round pick from the 2005 NFL Draft. Firstly, RB Ryan Mathews is still largely a question mark after a shaky rookie campaign. If Mathews cannot avoid nagging injuries in 2011, the Chargers will regret depleting their depth at running back.
Secondly, there is a chance the Chargers will trade for Carolina Panthers Pro Bowl receiver Steve Smith. This would indicate the team is going all-in in pursuit of a championship this season, an effort Sproles would surely bolster. Additionally, the thought of Philip Rivers dropping back and viewing targets including Antonio Gates, Vincent Jackson, Smith, Patrick Crayton and Sproles is downright tantalizing.
Because of this, the Chargers will do their best to stay in touch with Sproles during what figures to be a frantic free-agency period, and to extend him a competitive offer. However, more than anything, Sproles wants to be a bigger contributor on offense. If a team like the St. Louis Rams or Miami Dolphins offers more touches and more dollars, the Chargers will surely see their Lightning Bug fly out the door.
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Michael Lombardo is a long-time contributor to the Scout.com network. His analysis has been published by the NFL Network, Fox Sports and MySpace Sports. He has followed the Chargers for more than 16 years and covered the team since 2003. You can see more of his updates by following him on twitter.