Conventional wisdom tells us to rely more on those running backs who have performed at a relatively high level in the past. It's the idea that someone such as BenJarvus Green-Ellis has put up multiple 1,000-yard seasons, while rookie Giovani Bernard hasn't even sniffed regular-season action in the NFL. 

This conventional wisdom may also tell you to rely on Rashard Mendenhall instead of Stepfan Taylor with the Arizona Cardinals.

All this sounds fine and dany on the surface, but it really is the safe road to take. 

Why not go with upside over a verteran who has leveled out? Does it make much sense to think that Green-Ellis will go for another 1,000-yard season, especially after Cincinnati spent a second-round pick on Bernard this past April? Even just a mild decrease in carries of four or five per game would limit Green-Ellis to bench player in standard leagues. Based on recent performances, he'd likely go for less than 800 on the ground with just four touchdowns. 

At the very least, Bernard will pick up those 80 attempts and the 100-plus attempts that backup Bengals' running backs saw last season. That's 180 attempts for a running back that has the ability to put up well over four yards per rush. This is working off the basic premise that Benard will not overtake Green-Ellis as the Bengals' primary running back at some point relatively early in the season. Based on talent alone, that's not the premise many within the scouting community is willing to work off. 

In fact, a strong argument could be made that Bernard will go for over 1,000 yards and tally 40-50 receptions as a rookie in 2013. That makes him a decent option as a bottom-tier RB2 or solid FLEX option. 

Mendenhall and the Cardinals' running back situation is a completely different story. Rookie Stepfan Taylor nabbed 20 attempts in Arizona's preseason opener, while Mendenhall didn't see action. The Cardinals went out there and selected Taylor as well as Andre Ellington in April's draft. The addition of the former Pittsburgh Steelers starter was just as insurance in case those two and Ryan Williams are unable to prove they can formulate some sort of a viable backfield. 

For his part, Williams is still on the sideline with an injury and has played in just five of a possible 32 games in his first two NFL seasons. He's a non factor at this point. 

While Taylor will not give you five yards per rush or a 1,700-yard season, he has the capability to shoulder the load for Arizona in 2013. In fact, he's likely the only viable running back in the mix with the Cardinals that has that ability. Of course, this is precluding a struggling and often-injured Mendenhall from the conversation. 

While these were the first two running backs I decided to look at, other rookies also stand a chance to make a strong impact in 2013. 

Reports from Denver Broncos camp seem to indicate that Ronnie Hillman is in the lead for their starting running back position. This is based off of what has been a solid offseason performance for the second-year back, but it's also based off John Fox's philosophy of going with the "veteran" over the rookie. We have seen this in the past with both the Broncos and the Carolina Panthers. 

Even if there is an equal distribution of carries with Hillman and 2013 second-round pick Montee Ball, Denver will have enough attempts to go around. It averaged over 30 attempts per game last season, even with Peyton Manning at quarterback. John Elway and Co. also thought it was necessary to go out there and spend a high-round pick on a running back. There are absolutely zero indications that Denver plans on slowing down its rushing attack this season. 

Based on previously workload, Ball is the odds-on favorite to get a majority of Denver's attempts. 

Hillman didn't average more than 23 attempts in either of his two seasons at San Diego State, while Ball has averaged 25 or more attempts in each of his last two years at Wisconsin. 

This may not seem like a dramatic difference, but it's important to note that Ball was doing this in the Big Ten, while Hillman was going up against less-than-stellar competition with the Aztecs. 

The over/under of either of these running backs going for more than 1,000 yards isn't too good. That being said, Denver will be able to rely on Ball to shoulder the load more than it will be able to rely on Hillman. 

Le'Veon Bell is the most likely of all these rookie running backs to put up great fantasy numbers. While he didn't play in the Pittsburgh Steelers preseason opener, he's facing less competition at running back than the others. Both Jonathan Dwyer and Isaac Redman leave a lot to be desired and failed to really perform last season. 

In addition, Bell seems to fit Pittsburgh's downhill running game a great deal. He's a power running back, who does a great job gaining yards between the hashes. By virtue of his 382 rushing attempts last season at Michigan State, Bell won't have an issue shouldering the load. 

Using advanced metrics, I will project what each rookie running back will do in 2013. For the purposes of this article and the projections below, I am not including Green Bay's two-headed rookie monster at running back. The purpose of this article was simply to point out that the philosophy of going veteran over rookie doesn't make a whole lot of sense a majority of the time.