In the realm of fantasy football, using early picks on rookies is usually a dicey proposition. It’s not often that a rookie comes into the league and is able to quickly establish fantasy relevance, though a few players do break through every season. Typically, a few running backs make an immediate impact, as that is the easiest position to transition to from college. In 2007, Adrian Peterson and Marshawn Lynch were drafted for the sole purpose of taking over their team’s running game, and they both went on to have successful seasons. Even an undrafted rookie like Ryan Grant can have an impact if he finds the right situation. (I was lucky enough to snatch him off the waiver wire before he went on his 10-game train ride to fantasy stardom. I went on to win the title in that league despite disappointing performances from two of my keepers – Shaun Alexander and Marvin Harrison.)

Last year’s wide receiver crop was a bit thinner. Dwayne Bowe was the top rookie, finishing in the top 20 in most scoring formats. This was an upset considering all the fantasy owners that were drooling over Calvin Johnson’s intangibles before the season started. James Jones and Anthony Gonzalez flirted with fantasy relevance, but otherwise rookie wideouts didn’t make much of an impact in 2007. But every year, it seems like there’s one or two that become starter-worthy. (Who can forget Marques Colston’s 2006 campagin?)

So let’s take a look at this year’s top fantasy rookies and see who’s likely to make an impact.

RUNNING BACKS

1. Jonathan Stewart, Panthers (pictured)
Stewart is a power back and that’s the Panthers’ style. DeAngelo Williams has been something of a disappointment, so if Stewart runs well during the rest of the preseason, it’s not inconceivable that he could earn a starting role. However, durability is a concern with Stewart, so it is more likely that the Panthers will split carries to keep him fresh and injury-free.

2. Darren McFadden, Raiders
Due to his combination of strength and speed, some compare the #4 overall pick to Adrian Peterson. McFadden joins Justin Fargas and Michael Bush in the Raider backfield. Fargas had something of a breakout season in 2007 and Bush is running very well in camp, but McFadden will still get his touches. The team has said they’d like to use McFadden like the Saints used Reggie Bush in his rookie season. Oakland won’t want to wear him out, so this looks like a RBBC for the time being.

3. Matt Forte, Bears
The Bears drafted Forte in the second round to shore up a struggling running game. Cedric Benson was a bust, but the offensive line has been suspect for a couple of years now, so there’s no telling just how much Forte will help Chicago’s ground game. He has looked solid in the preseason, and should be a solid RB3 in most fantasy leagues.

4. Kevin Smith, Lions
Smith is one of the more promising rookies simply because the Lions don’t have any other good options at tailback. Tatum Bell and Brian Calhoun haven’t made their mark, so it’s Smith’s job to lose. He has had durability and character issues during his career, so there is some question as to whether or not he can hold up to the wear-and-tear of a 16-game season. Still, given the lack of competition, he’s an intriguing middle-round fantasy pick.

5. Chris Johnson, Titans
The diminutive speedster seems to be earning a bigger and bigger role as the preseason wears on. LenDale White will get most of the work between the tackles (and, presumably, around the goal line), but Johnson will see a lot of work in the passing game and as a change-of-pace back.

6. Ray Rice, Ravens (pictured)
With Willis McGahee coming off of knee surgery, and Rice impressing in camp, there’s a real possibility that the rookie starts at tailback in Week 1. There are rumblings that the team is none too happy with McGahee’s (lack of a) work ethic, so Rice’s value is enhanced in keeper or dynasty leagues.

7. Rashard Mendenhall, Steelers
The Steelers raised some eyebrows (including Willie Parker’s) when they drafted Mendenhall in the first round. For now, they see him as a complement to “Fast” Willie, but he should eventually turn into an every-down back. The writing is on the wall for Parker; it’s just a matter of time before Mendenhall takes over as the Steelers’ feature back.

8. Steve Slaton, Texans
Ahman Green is hurt. Big surprise. Chris Brown is hurt. Big surprise. Somebody has to carry the ball in Houston and Slaton is second in line after Chris Taylor. Slaton has better speed, but Taylor is a little more physical. If Green and Brown continue to miss time, we might be looking at a Taylor/Slaton RBBC in Houston.

9. Felix Jones, Cowboys
Jones is the “lightning” to Marion Barber’s “thunder,” but this isn’t a timeshare. Barber is the main back, and Jones will be used to spell him and to add some punch out of the backfield in the passing game. Barber owners should definitely target Jones as a handcuff in the late-middle rounds.

WIDE RECEIVERS

1. Eddie Royal, Broncos (pictured)
Having already earned the starting spot opposite Brandon Marshall, Royal seems poised to be the top receiver in this year’s rookie class. He’s fast and quick, but he’ll struggle against the more physical corners. He should be able to post solid WR3/WR4 numbers if he and Jay Cutler can find a groove.

2. Josh Morgan, 49ers
Morgan was just a sixth round pick, but the lack of talent in the San Francisco WR corps has him slated as a starter to begin the season. He’s had a great preseason and should produce in Mike Martz’ pass-happy offense.

3. DeSean Jackson, Eagles
With Kevin Curtis sidelined, the door is open for Jackson to start opposite Reggie Brown. He’s smallish, but has excellent speed and can make defenders miss in the open field. Keep an eye on this WR2 battle as camp progresses, because the winner will have value in deeper leagues.

4. Donnie Avery, Rams
Avery is expected to be the Rams’ third receiver and will see most of his time in the slot. He is fast, shifty and agile, but he’s undersized. He’s a possession receiver with speed, and only Drew Bennett stands between Avery and a starting job.

5. James Hardy, Bills
Hardy is battling a bad hammy in the preseason, which is stunting his development. If all goes to plan, he’s going to be the starter opposite Lee Evans, but if he can’t get healthy by the start of the season, he’s a late-round flier at best.

6. Jordy Nelson, Packers
Nelson looks like the prototypical West Coast Offense wideout. He’s big, strong and is a good route runner. He projects to be fourth on the depth chart behind Greg Jennings, Donald Driver and James Jones, but keep an eye on Jones’ recent knee injury. Nelson stands to benefit if any of those three go down.

7. Devin Thomas, Redskins
Thomas has had a rough preseason thus far. Coming off an injury, he had a couple of drops in his preseason debut. If he gets his act together, he could overtake Antwaan Randle El as the Redskins’ WR2, but right now it’s not looking too good.

8. Early Doucet, Cardinals
Doucet is just returning from a hamstring injury, so he’s behind and probably won’t be able to win the WR3 job before the season starts. That said, with Anquan Boldin in a consistently bad mood, Doucet could be pressed into action if the Cards decide to move Q.

9. Limas Sweed, Steelers
Sweed is big, strong and fluid, but has yet to pass Nate Washington on the depth chart. With Santonio Holmes and Hines Ward also ahead of him, the Steelers are in no rush to press the rookie into duty before he’s ready.

TIGHT ENDS

1. Dustin Keller, Jets (pictured)
Chris Baker is the Jets’ starting TE, but Keller has been used as a slot receiver and red zone threat during the preseason. Brett Favre loves throwing to his TE, so Keller could make for a capable TE2 as the season progresses.

2. John Carlson, Seahawks
Seattle drafted Carlson in the second round for a reason, and Mike Holmgren recently said that Carlson is the player that they thought he was. He hasn’t been running much with the first team, but he’s a guy to keep your eye on in deeper leagues.

QUARTERBACKS

1. Matt Ryan, QB, Falcons
Ryan has been named the starter in Atlanta, which means he’s on the fantasy radar, especially in leagues that start two QBs. He has played pretty well in the preseason and has a few offensive weapons to utilize, so a decent season isn’t out of the question. It’s tough to get excited about a rookie QB, however.

2. Joe Flacco, QB, Ravens
Flacco is in the midst of a three-way QB battle with Troy Smith and Kyle Boller. His numbers look pretty good, but he’s done most of his damage against the opponents’ scrubs.

3. Chad Henne, QB, Dolphins
The Fins didn’t bring Chad Pennington in to ride the bench, so Henne will be holding the clipboard for the time being. If Miami gets knocked out of the playoff race early, they could turn to the rookie to get him some experience.