Fantasy Sleepers

At its core, Fantasy sports are very similar to investing in the stock market. You want to buy low, and sell high. Get the maximum value out of every deal.

One part of the "buy low" concept is to draft "sleepers," or players that have yet to show impact, but have a lot of potential. Since they have yet to prove that they're going to be studs, you can acquire these players with lower draft picks, while you choose more proven studs in the first 5 rounds or so.

Here are some sleepers that you should look out for as backups, or if you miss out on some of the higher-end players at each position:

Quarterbacks:

No position is harder to learn in the NFL than QB. As a general rule, I try to look for (at least) one established veteran, and avoid rookies altogether. It's very rare that a Matt Ryan or Peyton Manning comes around and throws for over 3,000 yards as a rookie. So, Matthew Stafford can sit out on your league's waiver wire or free agent pool and and hold a clipboard until an injury on your team makes him a necessary add (Honestly, I don't wish that on you, but if it comes to it, he's not the worst option in the world).

Trent Edwards, BUF - Edwards played reasonably well last year, but didn't throw a ton of TDs. Enter Terrell Owens. Buffalo has a legitimate passing attack with Lee Evans and T.O. lining up on the outsides. Edwards has the targets and the running game to back him up, all he needs to do is put it in the end zone.
Projection: 3,200 yards, 21 TDs, 17 Turnovers.

Joe Flacco, BAL - There's no question, Flacco played well beyond his years last year. If not for Matt Ryan's incredible turnaround of the Falcons, I have very little doubt that Flacco would have won Rookie of the Year. But, what I really love about Flacco (for fantasy purposes only) is that his team went out and got him even more help on an offensive line that was already very good. I think Flacco will continue to ascend the ranks of the NFL QBs in real life, but for fantasy he's still just a quality backup with mediocre weapons.
Projection: 2,900 yards, 18 TDs, 12 Turnovers.

Running Backs:

I love picking up rookie sleepers at running back more than anything else in fantasy football (except maybe pulling off a really helpful trade). This year, Running Backs are especially plentiful. Finding the right one might be a bit of a chore, though, so here are my guesses for rookies (and a few non-rookies) that will help your team this year.

LeSean McCoy, PHI - I've mentioned this before, but McCoy has all the skills of Brian Westbrook in a younger package. Handcuffing an injury-prone star, like Westbrook, with a young player that could be a stud is a good strategy. Pick him up a round before you normally would, though, because the secret may be out already on this potential game-breaker.
Projection: 750 rush yards, 300 receiving yards, 6 total TDs.

Knowshon Moreno, DEN - He needs a lot of things to go right in order to reach his potential, but his ceiling is higher than any other back in this year's class. He can do it all and if his injury clears up and Kyle Orton avoids throwing the ball to the other team, Moreno could be a dominant rusher this year.
Projection: 900 rush yards, 200 receiving yards, 7 total TDs.

Ray Rice, BAL - Baltimore clearly has more than one sleeper. Probably one in each category, actually. I like Rice to have a good year because of the aforementioned offensive line that is further improved from last year's. Assuming Flacco doesn't turn into Rex Grossman (or Peyton Manning) overnight, the Ravens will be a ball-control offense that caters to lots of carries for Rice. He may lose out on some TDs, though, to Big Boy Le'Ron McClain.
Projection: 1,000 rush yards, 200 receiving yards, 8 total TDs.

Felix Jones, DAL - I was really on the Felix bandwagon last year before he got hurt. He can score from anywhere (and I love having RBs that return kicks, too) and he's got enough of a burst that even Marion Barber won't poach a ton of scores from him. Furthermore, without T.O., the Cowboys will likely opt for more of a running-based offense, meaning more carries for both Barber and Jones.
Projection: 750 rush yards, 300 receiving yards, 6 total TDs.

Wide Receivers:

Unlike running backs, rookie WRs rarely make a huge impact. And don't, under any circumstances, think that Michael Crabtree is doing himself any favors by skipping all of training camp. He's not off to a good start and in spite of his body type and build, I don't buy him as a legit NFL receiver. Just my opinion. Let some other idiot take him while you concentrate on players who will actually make an impact on your team this year.

Nate Washington, TEN - Yes, he's starting now, and yes, Jeff Fisher says that he plans on incorporating him heavily into the offense, but temper your expectations. Until he shows otherwise, he's a bench player with #3 or fringe #2 potential. Draft late, though and get a steal.
Projection: 55 catches, 800 yards, 5 TDs.

Mark Clayton, BAL - I told you Baltimore could have someone in every category, right? Derrick Mason already retired once this year and Clayton could be a number one receiver pretty soon. He has gone undrafted in 5 out of 6 mock drafts that I've done, but I have a feeling this could be a breakout year for him. Then again, it's just a feeling, so don't gamble your draft on it. Take him with your second-to-last pick (before your kicker, though) and it's a low-risk move that could pay off with a fairly solid #3 receiver.
Projection: 55 catches, 800 yards, 7 TDs.

Percy Harvin, MIN - Usually avoiding rookie receivers is the way to go, but when a team adds whole pages and plays to their playbook for you, there's probably a reason. He (like Devin Hester in Chicago) has the potential to break a play for a huge gain any time he touches the ball. You'll have to gamble a little to get him before other owners, but you could capitalize on the first big game he puts up and trade him for a more reliable threat.
Projection: 40 catches, 600 yards, 6 TDs.

Tight Ends:

Tight End is a fairly deep position this year. That doesn't mean that you shouldn't try for one of the top 3 or 4, but you shouldn't worry if they do pass you up.

Brent Celek, PHI - Just because everyone has been calling for him to get playing time. I could see him having decent value, especially if McNabb were to get hurt. Remember: Michael Vick's favorite target with Atlanta was Alge Crumpler.
Projection: 40 catches, 500 yards, 4 TDs.

Todd Heap, BAL - See? A player in every category! He's gone mostly unnoticed but if he manages to stay healthy he's a fairly good TE. You can get him late and if he puts up good numbers, consider it a well-deserved bonus.
Projection: 40 catches, 600 yards, 5 TDs.

Defense:

Washington Redskins - I don't think you should take them as a number one, but heck, if LaRon Landry takes another step and Albert Haynesworth stays healthy and lives up to his contract, you're looking at a fairly consistent and stingy defense that may be worth owning/trading.
No projection for defense.

Feel free to post some of your sleepers, too.
Don't forget to include projections!