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The Indianapolis Colts have had a problem in the run defense department for years.

In the past, it was partially by design, as an undersized defensive line that was built to rush the passer wasn't effective when asked to hold the line against a power run game. In the Chuck Pagano-Ryan Grigson era, it's been a mix of inconsistent and ineffective defensive line play and smaller, well-rounded linebackers that have struggled to get off blocks.

But in 2014, the Colts finally have the front seven that they've desired.

There are two experienced, talented defensive ends in Arthur Jones and Cory Redding, with a quality mix of veteran and young depth behind them in Ricky Jean Francois and Montori Hughes. There's a versatile pair of inside linebackers in Jerrell Freeman and D'Qwell Jackson. There's the edge-setting Erik Walden and pass-rush specialists Robert Mathis and Bjoern Werner on the outside.

Each one was hand-picked by the coaching staff and general manager Ryan Grigson, and only Mathis, who was re-signed by Grigson in 2012, remains from the Bill Polian era.

Even with all the new faces, it may just be one that brings it all together in 2014: nose tackle Josh Chapman, affectionately known by Colts fans as #Chapnado.

The 6'0", 341-pound lineman was drafted in 2012, the same class as most of the Colts' young faces of the franchise (Andrew Luck, T.Y. Hilton, Coby Fleener, Dwayne Allen), and was known as a dominant run-stuffer. But Chapman was recovering from a torn ACL and a torn meniscus in his left knee, an injury that he played through and put off surgery for three months. The injury forced his drop in the draft, and the Colts were able to draft a high-ceiling player in the fifth round.

The road to recovery was a long one, lasting his entire rookie season, but Chapman was ready when 2013 rolled around. Chuck Pagano called him a "900-pound safe" during training camp after he took out four offensive linemen in a single play, and Chapman played over 400 snaps in the season.

Chapman was good, but not great during what was essentially his rookie season, racking up a positive-2.3 grade against the run from Pro Football Focus (subscription required), but a negative-5.6 passing grade. Chapman flashed his ability though, enough that Colts Authority's Ben Gundy called Chapman a future star in his offseason film review.

So far in the preseason, Chapman looks to be taking that next step, and the Colts defense is benefiting because of it. Just ask Chuck Pagano, like Stephen Holder of the Indianapolis Star did:

It plays a huge role in the success of your run defense and stopping the run, when you've got guys that are big men but are also athletic and have good range . . . they're going to try their best and they're going to give their effort ... They command double-teams and they keep our linebackers free to make plays. But at the same time, they do their job and they're strong.

If you watch Chapman for any length of time this preseason, you'll see all of those qualities for the third-year pro.

At over 340 pounds, it takes a lot for an offensive lineman to move Chapman, and thus, many running plays look like this when Chapman is in the game:

NFL Game Rewind

Chapman rarely has given up ground in the preseason and always seems to have awareness of where the hole is supposed to be. Watch above as he pushes the whole pile to the right to stop Rashad Jennings in his tracks.

It's that combination of awareness and power that allows Chapman to be around the ball as much as he is. Defensive tackles aren't necessarily supposed to rack up a lot of tackles, but Chapman has excelled so far this preseason in that area.

With three run stops in 15 run snaps, Chapman is tied with Jacksonville's Ziggy Hood for the fifth-best run stop percentage in the league among defensive tackles so far this preseason, according to Pro Football Focus.

It was on display in the very first play of the game against the New York Giants as well.

NFL Game Rewind

On the play, the center is assigned to Chapman, and the hole is supposed to be in the left "A" gap between the center and the left guard. If all goes according to plan, the fullback would be responsible to block LB Kelvin Sheppard and the running back would just have the safety to beat.

NFL Game Rewind

At first, it seems that the play is going decently well for the Giants. The two outside defenders have been sufficiently sealed out of the hole, and the fullback has a wide-open hole to lead through. Chapman is moving to his right, however, and has not been sealed off.

It looks as though Chapman and Sheppard could collide and possibly knock each other out of the play, but Chapman, always aware, makes a move right around the linebacker and fullback collision. This effectively sheds his block and puts him right in position to take on the running back head on.

NFL Game Rewind

Notch it up as another run stop for the 900-pound safe.

NFL Game Rewind

But Chapman isn't just a big body in the middle, his mobility is surprising for a man with his mass. Against the Giants, that mobility was key to keeping the Giants from running sweeps and tosses to negate his presence in the middle.

Late in the season last year, Chapman occasionally would lose his balance and find himself out of the play, but he shows great persistence and and agility on the Giants' second run of the game to get all the way to the opposite side of the field and stop a run play.

NFL Game Rewind

NFL Game Rewind

Again, you see Chapman's awareness at work, as the tackle keeps his head up and his eyes on Jennings throughout the entire run, despite the mass of people between them.

NFL Game Rewind

It's a little difficult to see without the All-22 film, but Chapman manages to make first contact with Jennings, bringing him down for a gain of just three yards.

But even when he's not directly involved in a play, Chapman makes a big impact with his awareness of where plays are going and his glove-like arms that swallow up offensive linemen. When #Chapnado became Chapman's nickname last year, it was mostly because of the current popularity of the SyFy movie Sharknado. But the name is actually quite fitting, given how Chapman pulls offensive linemen into his clutches.

Early in the second quarter, the Giants once again tried to run a toss to the right side, this time with an extra tight end on the strong side. The key to the play is the second-level blocks, especially those on the right side of the formation.

NFL Game Rewind

The above diagram is how the play is supposed to play out, but not how things eventually come together.

The right guard needs to get out and block D'Qwell Jackson so the pulling tackle can take out one of the defensive backs on the edge. Then there's just one more defensive back for the fullback to take care of and Jennings is home free.

Unfortunately for the Giants, Chapman has other ideas.

NFL Game Rewind

While the guard attempts to jump off the snap and get to the second level, Chapman reaches out with his left hand and corrals him. This, of course, while holding off the center with his right hand (behind the mass of bodies).

With Jackson now unaccounted for, one of the lead blockers on the edge has to pick him up. Justin Pugh, the pulling tackle, doesn't see him right away as he comes around the edge, so he goes after Sergio Brown. The fullback is then left with Jackson, who attacks with a vengeance. Meanwhile, Marcus Burley, who was the other defensive back on that side, is home free (just off the screen to the right).

In this frame here, you can see that Chapman is still holding off the two blockers, and he impedes the center just enough so Burley can come from offscreen and take down Jennings, who was forced to make an adjustment when Jackson runs over the fullback.

Chapman (red) even manages to get himself far enough over toward the play that Jennings had nowhere to cut toward, even if he tried to make Burley (yellow) miss. It really was an impressive play all-around for the Colts defense, but it all started with Chapman in the middle.

The impact of Arthur Jones on the line has been noticeable, but it's really Chapman who is igniting the revolution. While Pro Football Focus is not the authoritative voice, Jones has just a negative-1.9 grade, while Chapman has an impressive positive-2.0 in just 23 snaps. Jones has also failed to record a single stop, while Chapman leads all non-linebackers with three.

Don't take this as a slight toward Jones. He's a good player and will be fine once that regular season starts. Rather, it's simply evidence toward the fact that it's Chapman that's heading the Colts' stout run defense so far this preseason.

The New York Jets and Giants are not among the NFL's top offenses, but the Colts still held them to 157 combined yards on 55 carries, a 2.85-yard average. The first-team front seven has looked particularly stout in that time, and Chapman is the giant mass that it all revolves around.

If he can continue to create space for the linebackers while making plays at the same time, the Colts could have their best run defense in years.

All statistics and snap counts come from Pro Football Focus (subscription required) and Pro Football Reference unless otherwise noted. All training camp observations were obtained firsthand by the reporter unless otherwise noted.

Kyle is an NFL and Indianapolis Colts analyst for Bleacher Report and the editor-in-chief of Colts Authority. Follow Kyle on Twitter for more stats, analysis and general NFL analysis.