Rookie RBs can make difference

It did not take long for the Minnesota Vikings to realize what they had in Adrian Peterson -- arguably the best running back in the NFL.

Each year, the biggest dilemma facing most fantasy football owners is when to draft a rookie. For the most part, the decisions are exclusively within the running back pool. Draft a rookie too high who doesn't perform and the unknown factor haunts you. Now you're stuck with an underperformer for the entire season, hoping your faith in him eventually pays off.

Take a chance on a rookie runner who performs well and that's a solid way to win your league. Even though rounds 1 through 5 are pretty set in order of selections, with a few variances, the rookies can be the difference makers.

Last season, the top running back chosen in the NFL Draft was Darren McFadden. Many owners had their doubts about him because he was with the Oakland Raiders in an unsettled offense. But taking a top-drafted runner usually pays dividends, as with Peterson in 2007.

McFadden didn't work out so well last season. We all know how Peterson turned out. He rushed for 1,341 yards and 12 touchdowns in 14 games as a rookie, and he has 3,101 rushing yards and 22 TDs in two seasons.

Bears second-round pick Matt Forte didn't have a great preseason, but he started every game before the regular season. Once it was go time, Forte put forth one of the best seasons of all backs, with more than 1,700 combined yards and 12 TDs.

Chris Johnson, the Titans' 23rd pick overall, and Texans third-rounder Steve Slaton each helped fantasy teams.

It's the luck of the draw, but it's also about having some of these players scouted and knowing where the team appears to be going regarding the incumbent back and injuries and how they have looked in training camp and preseason. There are some rookie gems who probably will make a difference.

Here's a look at the top rookie running back candidates for 2009, including where some owners have drafted them in fantasy leagues from around the Internet (based on a standard 10-team league). The backs are listed according to their order of selection in the NFL Draft.

• Knowshon Moreno, Denver: Averaging about a sixth-round pick in most drafts, Moreno has had only three carries in preseason because of injury but should be ready by Week 1. It's a crowded Broncos backfield, but Moreno gets the nod if healthy because of the pressure on the coaching staff to use a product of the Jay Cutler trade.

• Donald Brown, Indianapolis: Brown is being picked early in the ninth round. He's a great candidate because Joseph Addai seems certain to get hurt. The past two seasons, Colts backups have been prominent thanks to Addai. Brown is a hard runner with good hands, and Peyton Manning will utilize him.

• Chris Wells, Arizona: Most have picked him in the eighth round. He has the ability to be good between tackles, but his durability -- a question mark at Ohio State -- continues to be a concern as he has missed the preseason.

• LeSean McCoy, Philadelphia: He's an 11th-round pick by most, even though he has started all the Eagles' preseason games. Brian Westbrook played his first game Thursday since surgery, but he's always a question mark.

• Shonn Greene, New York Jets: Starter Thomas Jones has been durable but is in his 10th year, well past the usual shutdown time for running backs. Greene's only shot is if Jones slows, but he might be worth a look around the 10th round.

• Glen Coffee, San Francisco: He's a 15th-round pick by most, even though he leads all NFL backs in preseason yardage. Frank Gore is the starter, but look for coach Mike Singletary to get Coffee in the game. He makes things happen. Coffee is worth the risk earlier than the 12th round.

• Frank Summers, Pittsburgh: There were visions of "The Tank" as the Steelers' new goal-line back, but a hamstring injury has kept the former UNLV back out of the running.

• James Davis, Cleveland: Undrafted by many, he has had a great camp and preseason, including an 81-yard TD run that has impressed coaches. Davis is much quicker than Jamal Lewis and could be starting soon, making him around a ninth-round choice or better as more news comes.

Micah Roberts is a Las Vegas-based writer who will contribute weekly fantasy football outlooks for the Las Vegas Review-Journal. He can be reached at MM.Roberts7@gmail.com. ON THE WEB: Roberts ranks the top fantasy players at quarterback and running back.