Carter's Classroom grades: Fullback/tight end

While not the playmakers at wide receiver and running back or the bruisers on the offensive line, these are the guys who pull double duty.

The absence of Heath Miller was an obvious hole that needed to be filled, which is why the Steelers went out and got LaDarius Green, a slimmer but better receiving tight end who could make plays down the field for Ben Roethlisberger.

But like many of the other positions groups, this part of the team had their depth tested due to injuries, seeing Green and Xavier Grimble miss parts of the season and forcing Jesse James to step up along with David Johnson to return to the team.



ROOSEVELT NIX

Since the departure of Dan Krieder after Super Bowl XL, the Steelers have lacked that real full on bruiser of a fullback who could be a dominating lead blocker. They found that last year in Roosevelt Nix, and he continued to be just that in 2016.

Strengths: Nix made his name in 2015 with big hits and being a crucial blocker at key points of attack for both Le'Veon Bell and DeAngelo Williams. Though Nix missed multiple games due to injury, he still was of great value to the team.

Nix is a big back to handle, his 5-foot-11, 260-pound frame mixed with a solid group of fundamentals make for trouble against the biggest linebackers in the hole.

Watch how Nix (45) deals with a blitzing middle linebacker who is coming up the A-gap uninterrupted:



Nix always has a low pad level and can explode through opponents all while maintaining solid fundamentals like having a wide base, using his hands to get to the inside and extend to make sure he's in control.

Nix constantly does this both in tight spaces up the middle and out on the edge.

What makes him even more valuable is how his style mixes extremely well with Bell's running style. Watch how Nix runs into the hole with choppy feet, looking left and right to see where would be the best place to attack:



Not only does he get to Zachary Orr (54), but he blows him out of the hole and seals him away from the play.

If Maurkice Pouncey manages to block C.J. Mosley, this could be a touchdown, and Nix would've been a key part of it.

Weaknesses: Though not a major concern with all the playmakers on the roster, Nix's biggest weaknesses is that he's not that much of a receiving option.

He doesn't have the speed and is often taken out of the formation whenever the team needs to spread out the defense and at least threaten the defense with the pass.

He's not much of an option at tight end or an option as a runner from a hand-off. That means that when he's on the field, defenses can feel more comfortable predicting for the run.

While that also means the Steelers can play off those tendencies, Nix's lack of versatility on offense is a liability to consider.

Value: Nix is a free agent after next, which gives the Steelers another year to figure out what to do with him. He's a great lead blocker for Bell and is reliable tackler on special teams, but with the Steelers' fast-paced offense, there are questions if they could put a more versatile player on the team.

Nix is only 24 and takes up just more than $600,000 in cap space, which puts him at a good value to keep around. If he makes it through 2017 healthy and continues to play at the level he has, the Steelers might try to find a way to keep him around if he's open to a team-friendly contract.

LADARIUS GREEN

Green missed most of the season due to injury, which was disappointing, considering how much of a weapon he proved to be when he was on the field.

Strengths: Green was a cap casualty of the Chargers, which allowed the Steelers to scoop him in free agency. His resume of success with the Chargers featured multiple big plays down the field and out-running opponents.

When Green made it back from injury, his receiving threat added another dimension. Green's speed and size as a tight end make for a tough player to cover. Add that with solid route running skills and you have a target that's a threat on any point of the field for Roethlisberger.

Watch this play-action pass that Green is able to take for 35 yards:



Green runs a corner route underneath Sammie Coates' fly pattern, which gets him a lot of space from the safety to make this play.

Because he's faster, he gets separation on the inside linebacker who has to guard him, making for an easy target for Roethlisberger. Green's receiving skills were evident in each game he played, which made for a more threatening offensive game plan that Todd Haley could call, and added a tall option for Roethlisberger to find security in.

Weaknesses: The biggest knock on Green coming into the season was his run blocking. Green is a slimmer tight end who doesn't bring a lot of force into his blocking skills, more so relying on his size to get the job done with his arm length to keep defenders from getting inside on him.

While that's certainly letdown from the ever reliable Miller, the Steelers should have no problems accepting that if Green can be the playmaker he looks to be on film.

Value: Green's health is the biggest question to his value. He's scheduled to take up more than $6 million in cap space next season and is on the books until 2019, which is a solid chunk of money the Steelers have invested in having another weapon for Roethlisberger.

If Green's health can keep him on the field next season, it will most certainly make him a bigger commodity for the team. Especially if he's in the middle of a healthy offense that opens up more opportunities for him deep down the middle of the field.

JESSE JAMES

But what Green might have to watch out for is the emergence of James. He went from being a spot player to a consistent starter on the offense, hauling in 39 catches for 338 yards and three touchdowns. He brings balance to his game, which is what makes him a solid fifth-round draft pick about to enter his third season.

Strengths: James does what Green does not, in that he cannot only be reliable as a blocker on the line of scrimmage, but he's improved his blocking skills enough that he can be relied upon as a lead blocker at the point of attack.

Watch here how James comes from the left side of your screen to take on Landon Collins (21), one of the NFL's best safeties:



James stays patient as he comes down the line before he engages Collins. When he does, he lowers his shoulders and gets his hands inside, keeping him safe from any potential holding calls. Though he doesn't finish the block aggressively, he does let go at the right moment to avoid any chance of a holding call at the end of the play, just when he realizes he had given Bell the edge.

That's something I noticed consistently about James when he was blocking out in space. He proved to have a grasp on the situation in most instances, knowing where to go and how to block to best spring whatever playmaker was behind him. If you remember the first touchdown of the playoff game against the Dolphins, you'll remember it was James' seal block that sprung Antonio Brown down the sideline.

But for our next play to showcase James, we wanted to show his development as a receiving tight end. James was very unpolished in this department a year ago and still looked like he would need work to be a reliable option for Roethlisberger early this season.

But as he continued to gain experience, I saw him run sharper routes and learn how to work his way down the field while getting open for Roethlisberger.

Watch this play that was called back from being a touchdown in the AFC Championship Game:



James' man does a good job engaging with James' outside shoulder in an attempt to force him inside and pass him off to someone else. But James sticks to his corner pattern even gets separation to present a good target for Roethlisberger.

Weaknesses: The biggest factor that keeps Green's spot as a starter safe is that James is not much of a playmaker with the ball in his hands and won't win many foot races. He's a good player who can make catches, but he won't stretch the field nearly as much as Green.

Value: James' skills are built closer to the style of Miller. While he's not nearly the elite player Miller was, James possesses a more even spread of blocking skills mixed with enough receiving skills to get open and catch the ball.

Entering the third year on his rookie contract, James has a very good opportunity to impress upon the Steelers' front office that he can be the tight end of the future. If Green still remains injury plagued, look for James to step more into the role of Roethlisberger's safe check-down man in the offense, and potentially guarantee him a contract after his rookie deal is up in 2018.

That timing could work in the Steelers' favor. Green's deal ending in 2019 is back-loaded so that if the Steelers want to depart from him just before the last year on his contract, the team will save $4.5 million in cap space, while only losing just more than $1.1 million in dead money for that season. That means that if they like James and the unit behind Green, they might have the security to move on and save some cap space for other positions.

XAVIER GRIMBLE

One of the biggest question marks I had on the year was Grimble. At times, he looked like a prototype tight end who could catch the ball in space and get open against any defender, and at others , you wouldn't even notice him on the field.

Strengths: Grimble's best asset is his ability to get open and catch the ball. He has enough speed and is good enough a running his routes that he can use his frame to box-out opponents to present a good target for Roethlisberger down the field.

Take a look at his touchdown against the Bengals:



Grimble runs a bit of a banana route and gets matched up against a safety. He sets the safety up well with his route and turns his shoulders at the right time to present Roethlisberger with a solid window.

Once Roethlisberger throws the ball, Grimble high-points it and makes a good catch with just his hands before he falls into the end zone for the score.

Grimble scored in an almost identical manner against the Ravens at Heinz Field during the week 16 showdown.

Weaknesses: Grimble's biggest problem might be a lack of consistency. Though he looked like the perfect tight end at some points, he showed how unpolished he was in others. Running routes not as aggressively when he wasn't the main target or not finishing blocks out on the edge were occasional happenstance on his tape.

That on top of missing four games played a factor in his stats being so low on the season despite the team needing another receiving tight end in the absence of Green.

Value: Grimble takes up just more than $500,000 in cap space and is on the books until after next season. If he wants to earn a follow-up contract, he will have to prove more consistent of a player. That will be tough to do considering the Steelers have seen a lot of good in both James and Green last season.

His window to impress the Steelers will be small, so whether he's ready to make a play as soon as he's called upon might be the difference between him staying or going after 2017.

DAVID JOHNSON

A familiar face, Johnson was brought back into the fold when the Steelers were missing Nix, Green and Grimble at different parts of the season. Johnson doubles as a blocking tight end and a fullback in the Steelers' scheme, which increased his value to the team.

Strengths: Johnson's biggest asset to the team is his ability to block and get physical both in the running and passing game. While James and Green are better options as receivers, Johnson's primary purpose in the offense is to be an extra line of protection for Roethlisberger.

Let's take a look back at that big pass play to Green we looked at earlier, but from a different angle. Watch for Johnson (82) blocking on the right edge right next to where Green lined up:



Johnson engages with his man out on the edge and keeps him locked up for the entire play. He does a good enough job so Marcus Gilbert has nobody to block.

Johnson is a guy who knows his value in the NFL is limited. He has to be productive at the line of scrimmage, both in run and pass blocking, for teams to want to invest in him being on the roster.

Weaknesses: Case in point, Johnson was brought in for just last season so that he could fill in for both Green and Grimble's injuries. He ended up also putting in for the fullback position on occasion when Nix was injured.

Johnson like Nix in that he's not very much of a receiver. Though he gained 80 yards from seven receptions on the season, he's not a player who is going to burn a defense. Rather he's a guy who can be a check-down option out in the flat or at close range, as he's not a good receiver or an exceptional route runner.

Value: Johnson is a free agent again this season and most likely will be in a similar situation in 2017. If Nix, Green, Grimble or James go down to injury, the Steelers would love to bring back that familiar face who can work within their system well.

But other than that, Johnson might spend all of this offseason waiting for someone to call.

OVERVIEW

The Steelers have a good duo at tight end in Green and James. Grimble's athleticism adds a solid third option at tight end and all for relatively cheap outside of Green's contract. As those three continue to improve their connection with Roethlisberger, each could play a role in the Steelers' offense dissecting defenses as opponents try to key off on Bell, Brown and a returned Martavis Bryant.