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What do the DeMarco Murray, Le'Veon Bell, LeSean McCoy, Marshawn Lynch, Justin Forsett, Arian Foster, Eddie Lacy, Jeremy Hill, Frank Gore and Lamar Miller all have in common?

None of them were the first running back selected in their draft class, yet they comprised the NFL's top 10 rushers in 2014.

As talented as this year's running back class is, the odds are in the favor of those who aren't as highly rated to eventually go on to have better careers.

The 2015 running back class is deep and talented. Players such as Georgia's Todd Gurley and Wisconsin's Melvin Gordon are in consideration to become first-round selections. Yet, an unheralded prospect from the Northern Iowa Panthers displays the type of talent that could make him into an impact player from Day 1 and eventually develop into a true workhorse for his team.

David Johnson may not elicit the same type of response as the aforementioned prospects, but his draft stock continued to rise at the NFL combine in Indianapolis. Plus, Johnson may represent a far superior value for a team compared to those backs being considered in the first two rounds.

Everything starts with Johnson's stature and raw athleticism.

NFL teams certainly prefer running backs who can take a pounding. The Northern Iowa product is a chiseled 6'1" and 224 pounds. Usually bigger backs aren't as quick as their counterparts. This isn't true of Johnson, though.

Johnson's 4.50-second 40-yard dash was fourth-best among the running backs. He also posted 25 repetitions on bench press. Those were only the start of his strong overall workout. Bleacher Report's Dan Hope relayed a couple more impressive numbers:

When the running back's overall size is entered into the equation, Johnson's speed becomes even more remarkable. DenverBroncos.com columnist Andrew Mason provided some context:

Johnson's time was actually faster than the more highly touted Gordon, who weighed nine pounds less in Indianapolis.

The overall speed and athleticism is only part of the equation, though.

The running back's value lies in his ability to contribute on all three downs.

In four seasons with the Panthers, Johnson carried the ball 866 times for 4,841 yards. Each year, the running back's workload increased to the point where he become the team's primary offensive weapon.

Johnson is a talented runner, but he may be an even better pass-catcher. The running back finished second on his team during his senior campaign with 38 receptions—one behind the team leader—and 536 yards.

Not only does the Northern Iowa product display soft hands, he is also a competent blocker. Each of these traits were on display when Johnson participated at the Senior Bowl in Mobile, Alabama, last month. His natural ability to catch the ball was again on display at the combine.

The fact Johnson is an accomplished receiver was readily apparent the moment he entered pass-catching drills in Indianapolis, as NEPatriotsDraft.com's Mike Loyko noted:

Whichever team eventually selects Johnson could see immediate dividends within the passing game. The organization can then take its time by allowing the 224-pound back to grow into its lead back. Johnson could eventually develop into one of the game's top dual-threat running backs.

Bleacher Report's Ian Kenyon provided an excellent example:

Numerous running backs beyond the top-rated prospects have the potential to emerge as the best runner in this year's class. Boise State's Jay Ajayi, Minnesota's David Cobb, Michigan State's Jeremy Langford and others will attempt to stake their claim as the best running back in the class.

Johnson's combination of size, athleticism and versatility makes him the most likely candidate to explode onto the scene as a rookie, and the team that eventually selects the running back will look very wise after avoiding the top prospects in the class.

Brent Sobleski covers the NFL draft for Bleacher Report. Follow him on Twitter.