With Terrance Knighton an impending free agent and Jason Hatcher pondering retirement, Washington finds itself needing to add pieces to the defensive line. Fortunately, there are plenty of candidates to fill roles in the trenches in both free agency and the draft. There’s a good chance Washington dips into both pools of talent to help replenish its defensive line.

Big name: Malik Jackson, Broncos, age 26
The Broncos have repeatedly stated they would like to retain Jackson after their Super Bowl win. However, Denver doesn’t have too much cap room to work with and Jackson would be in high demand if he hits the open market. The 6-foot-5, 295-pound defensive lineman can play in a number of positions and techniques. He has spent most of his time as a 3-4 defensive end in Denver, which is where he would project to fit in Washington. But he can easily shift inside to defensive tackle in a four-man front.

Jackson offers quickness, which is tough for interior offensive linemen to deal with. But he’s also strong and capable of driving blockers back.

Here, Jackson lines up in the B gap between the left guard and left tackle.

He’s quicker off the snap than the guard, but just as importantly, he stays low to maintain leverage. The speed allows him to get his hands inside before the guard can react, but the pad level gives him the leverage to convert the speed to power and drive the blocker back.

The blocker attempts to fight back, but can’t gain any leverage because of Jackson’s hand placement.

By the time the ball is thrown, Jackson has driven the guard all the way back into the quarterback.

While this play didn’t result in a sack, it’s important to realize that interior rushers don’t put up the same sack numbers as edge rushers. What’s most important is that they are able to push the pocket and keep the quarterback from stepping up into the pocket to avoid the edge rushers. By driving his blocker back into the quarterback, Jackson did his job.

Jackson draws praise for his ability to rush the passer from the interior, but he’s also a stout run defender.

On this play, the Lions bring in rookie guard Laken Tomlinson as an extra blocker. He and left tackle Riley Reiff work a combination block on Jackson.

Reiff gets a good punch to the chest of Jackson, almost turning him around away from the direction of the play. But Jackson stays with the play, not allowing Tomlinson to secure the block. Jackson recovers to get inside and control his gap.

The Broncos force the running back to cut back towards Jackson, who is quick to pounce on the opportunity and make the tackle.

Jackson might be one of the most expensive free agents on the market. He’ll have plenty of suitors, which will only lead to a higher price. But having only just turned 26 last month, he’s young enough to be productive over the life of a long-term contract. It’s not easy to find guys who can consistently provide pressure inside, which might make Jackson an option for Washington.

[More free-agent fits: Wide receivers | Safeties | Running backs]

Good value: Damon Harrison, Jets, 27
While the Jets are focused on Muhammad Wilkerson, another player along their defensive line is set to become a free agent. Nose tackle Damon Harrison isn’t a particularly prolific pass rusher, having made just 1.5 sacks in the past three years. But that’s not what you want from a nose tackle. Harrison is a big-bodied run stuffer. He’s 6-4, 350 and does a good job clogging up rushing lanes for opposing running backs.

Here, Harrison lines up as a one-technique nose tackle, in the A gap between the center and right guard.

The Texans quarterback and running back both start by faking a run to the right before redirecting to the left. Harrison takes position the the A gap, maintaining his position against the center while keeping his eyes in the backfield. He notices the back changing direction.

Harrison works back across the center, using a strong swim move to get past and disengage. From there, he fills the rushing lane and makes the tackle for no gain.

Washington’s defense gave up too many plays in the running game this year. Part of that was because of its inability to adjust to change of direction. Often defensive lineman would get reached and washed out of the play as the running back cuts back. But Harrison proves that he can make the adjustments needed on a consistent basis to stay in plays.

This time, the Cowboys run a counter play.

Like before, Harrison takes up position in the A gap to the right side of the line. But as the running back cuts back, Harrison stays with the play.

Harrison reads the cutback from the runner and works his leverage against the center. He gets his hands inside and drives the center back towards the runner. Harrison closes the rushing lane, stopping the running back from picking up significant yardage.

With Knighton seemingly unlikely to be retained, Washington has a need at nose tackle. There are a few promising prospects in the draft, but nose tackle has historically been a tough position to get right. The chance to sign a proven player in Harrison could be an attractive option for Washington.

Under the radar: Jared Crick, Texans, 26
Crick isn’t a particularly flashy player and won’t generate many sacks, as he has only 5.5 in his four-year career. He would most likely be a rotational player for Washington as a run defender who substitutes out on third downs and in nickel and dime packages. But that doesn’t mean there isn’t a role for him.

Here, the Dolphins run the ball directly at Crick, who faces a double team from the right guard and tackle.

Crick plays low, enabling him to withstand the combination block. He holds his position until the tackle peels off to pick up a linebacker.

Crick stays in his gap as he waits for the running back to approach the line of scrimmage. Crick then uses a swim move to disengage with the guard and begin his pursuit of the back.

Crick closes the gap on the back quickly and makes the tackle for a minimal gain before the back can get outside.

Maintaining gap integrity is something Crick does well. If a defensive lineman gets reached or washed out of their gap, it makes the job harder on the linebackers. But Crick is reliable and can be trusted to keep his gap occupied.

Like before, Crick lines up outside the right guard in a four-man front. The Saints elect to run the ball inside.

Crick stays low off the snap and gets under the right guard. He then takes up his position in the B gap as he reads the quarterback and running back in the backfield.

The Texans do a good job closing lanes inside, forcing the back to try and bounce his run outside. But Crick maintains his gap and gets off his defender as the back approaches, making the tackle for a loss.

Crick shouldn’t be particularly expensive because of the role he plays, but its a role that could be valuable to a team that struggled against the run last season. Washington could opt to sign Crick on the cheap, but may just decide to look to the draft to develop their own guy instead.

Mark Bullock is The Insider’s Outsider, sharing his Redskins impressions without the benefit of access to the team. For more breakdowns, click here

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