I love this time of year. After seven weeks, we have a good sample size to work with and can start trusting the numbers more as we (hopefully) prepare our rosters for the playoffs. This week's studs are two running backs who haven't overwhelmed, but have quietly been very efficient and will likely be key pieces on championship fantasy rosters. As for the duds? They both come from a team whose owner may want to take a closer look at some of his recent acquisitions rather than spending his time bashing Peyton Manning.

Note: For an explanation of Net Expected Points (NEP), read the intro to this article.

NEP Studs

Le'Veon Bell (0.02 NEP/Rush, Ranked 8th of 39 Qualified Running Backs)

Earlier this week, I touched on why Bell would make a great trade target for Doug Martin owners, and I'll expound on that idea here.

Bell's stats don't jump off the page: 51 carries, 184 yards, and two touchdowns in three games. While his yards per carry average currently sits at an underwhelming 3.6, that number is skewed by a 16 carry, 34-yard stat line against the New York Jets in Week 5. Nobody runs on the Jets.

The key for Bell is volume. He's received 59 touches so far this season, which averages out to 19.67 per game. When a player has mediocre stats but stands out in net expected points metrics, you can usually expect that player's fantasy stats to catch up as long as he is getting sufficient volume. In this way, Bell differs from Marques Colston, who also has fared well within the net expected points metric, yet has (somewhat surprisingly) not gotten enough targets to be a fantasy asset.

Bell was Pittsburgh's second-round draft pick, and is by far their best option in the backfield (sorry, Felix Jones), so expect Bell to get as much work as he can handle. With rookie running backs, earning the trust of the coaches and the quarterback is always important. Bell checks out in that regard, as head coach Mike Tomlin and quarterback Ben Roethlisberger both have spoken highly of Bell over the past few weeks.

Bell has played 76 percent of Pittsburgh's snaps since his return, and as he gets more acclimated to the pro game, that number may very well go up. He has already proven he can handle a heavy load, racking up an insane 414 touches in 13 games in his senior year of college at Michigan State.

The only thing holding me back from saying Bell will be a surefire RB1 is the fact that he has yet to break off a long run. His longest run is a pedestrian 11 yards, he's only broken four tackles, and he's made some questionable decisions as far as bouncing runs outside. He has exhibited good patience at times as well, but Pittsburgh's offensive line is mediocre at best. Then again, remember Rashard Mendenhall was a very productive fantasy running back in Pittsburgh despite always putting up underwhelming yards per carry numbers.

The fact that Heath Miller is Pittsburgh's only other legitimate red zone threat also works in Bell's favor. He'll likely get a decent amount of touchdown opportunities.

We currently project Bell as the 13th-best running back for the rest of the season, but you better believe he has RB1 upside.

Alfred Morris (0.04 NEP/Rush, Ranked 6th of 39 Qualified Running Backs)

Some Morris owners may have hit the panic button after Roy Helu's three-touchdown outburst last Sunday, but rest assured, Morris is still balling.

Despite Helu's big day, Morris actually received a season-high 19 carries against the Bears last weekend. His yards per carry average is up almost half of a yard over last season's (5.2 to 4.8) too. He is also second in the league in yards after contact, behind only Adrian Peterson. Since we're talking about Peterson, I should mention Morris averages more net expected points per rush than All Day as well.

It's understandable why some owners are frustrated with Morris: his 11.2 standard points per game is more like an RB2 than an RB1. Keep in mind that the Redskins started the season out on a bad note, trailing for much of their first two games. As a result, he only averaged 12.5 carries in those games. As the Redskins have started to come around over their past four contests, he has benefited to the tune of 16.5 carries per game. Barring catastrophe, I expect that average to continue throughout the season. Remember, he finished third in the NFL in carries last season.

Morris currently has the 14th-most standard fantasy points amongst running backs. All he needs is one big game to leap into the top-10 consideration. I expect that to happen, and we still project him as an RB1 the rest of the way.

NEP Duds

Trent Richardson (-0.14 NEP/Rush, Ranked 33rd of 39 Qualified Running Backs)

With all the eggs Richardson has laid this season, the Colts should just order bacon in bulk and serve every fan a complete breakfast at Lucas Oil Stadium. You know there's something wrong when you make the Browns look like they made an intelligent football decision.

60 yards. That's Richardson's highest rushing yardage output in 2013 through seven games. 60 freakin' yards. To add insult to insult (not a typo), he amassed those yards against the lowly Jaguars, who give up the second-most fantasy points to running backs and the sixth-most net expected points per rush in the whole league.

Between the Browns and the Colts, Richardson has amassed a total of -15.20 net expected points rushing. In other words, he's played two touchdowns below expectation already this season.

Richardson's 3.1 yards per carry is putrid. When a running back struggles, it's usually a good bet that his offensive line is struggling as well. While the Colts offensive line is far from spectacular, they do rank seventh in the league in adjusted line yards, which measure an offensive line's effectiveness independent of running backs. What's more, backup Donald Brown is averaging 5.9 yards per carry with the same offensive line. This is the same Donald Brown who couldn't surpass Vick Ballard or Delone Carter on the depth chart a season ago.

When watching the tape, I noticed the Colts run a lot of the same plays for Richardson and Brown. In Sunday night's game versus the Broncos, an inside run was called for Brown where he saw a cutback lane on the backside and picked up six yards. Richardson got a hand off on the same kind of play and the cutback lane was there for him too, yet he failed to see it and slammed into a wall of defenders for a negligible gain.

Is there any hope for Richardson? Sort of. The Colts were already committed to becoming a more run-oriented team this season under new offensive coordinator Pep Hamilton, and after losing Reggie Wayne for the season, it is very possible that they will lean on the run even more. Richardson has received 16.4 touches per game as a Colt, and that number could very well go up. However, with Brown playing so well, there's also the possibility that the backfield becomes a daunted committee.

Richardson does have some buy-low appeal because he's receiving a decent amount of touches. The Colts obviously wouldn't have traded away a first pick for him if they didn't intend to involve him heavily. He is showing tackle breaking ability; he's already broken 27 on 106 rushes. Now he needs to combine that power with better vision and decision-making.

We're projecting Richardson as a low-end RB2 for the rest of the season. Until he stops with all this inefficient running, his value will be touchdown-dependent. Is there a chance the light switch flips on? Sure. Until then, to borrow one from the great Bill Parcells: You are what your NEP says you are!

Darrius Heyward-Bey (0.49 Rec NEP/Target, Ranks 58th of 72 Qualifying Wide Receivers)

I swear I don't hate hate the Colts, I just thought it would be a good time to discuss the speedy but stone-handed Heyward-Bey since the Colts lost Wayne for the season.

To be clear, the Colts use DHB as a starter because he is a good run blocker. He currently trails T.Y.Hilton by 20 in the target department (55 to 35). However, DHB's role will expand with Wayne out. Can he be a viable starter in fantasy? Let's take a look.

Darrius Heyward-Bey's Career Ranks in NEP and Catch Rate (Min 35 targets)

As you can see, DHB has been a pretty inefficient receiver his whole career. In fact, he's been near the bottom of the league in both net expected points per target and catch rate in four of his five seasons. His four drops this season aren't helping his catch rate, either. While increased targets will no doubt bump up his fantasy production, DHB's inefficiency will keep him from being a reliable option.

DHB is best suited to be a deep threat, yet he's only averaging 10.6 yards per reception this season. He's seen only seven deep targets, while Hilton already has fifteen. Unless he's seeing a Wes Welker-like number of targets, DHB's lowly yards per reception average won't cut it fantasy-wise.

Since the Colts are not properly utilizing DHB's receiving skill set and he's always been an inefficient receiver, I don't see him turning into a viable fantasy starter. He might mix in a game or two that get you excited, but his inefficiency will limit his upside. He's a boom-or-bust WR4.