Washington center Spencer Long is a free agent this offseason. (Photo by John McDonnell / The Washington Post)

The Redskins¡¯ offensive line was meant to be a position of strength going into last season. However, they suffered a nearly insurmountable number of injuries that caused them to spend most of the season playing with backups in the trenches. If everyone returns healthy, the Redskins should feel comfortable about four of their five spots, with left guard the only position really needing to be addressed. Here?are some potential options in free agency.

Re-sign candidate: Spencer Long

Long has been drafted and developed in Washington. He entered the league in 2014 as a guard and has since switched to center. His knowledge of the system and positional versatility should be appealing traits to the Redskins, as should his athletic profile.

Gruden likes his interior offensive linemen to be stout, but capable of working out in space on screens. Early in the season, before injuries took over, the Redskins were a very good screen team.

Here, Long is tasked with initially blocking the defensive tackle to his left before releasing out to the flat and then leading the way for Chris Thompson.

Long and left guard Shaun Lauvao do enough to prevent the defensive tackle from blowing up the screen before working out in front of the screen. Long identifies a defender working from deep to try to make a tackle on Thompson and gets himself in the way before cut-blocking him, taking the defender out of the play.

Long is a versatile center who is effective in both zone and power schemes with the athleticism to pull to the edge or get out in front of screens. However, he was one of the many offensive lineman struck by the injury bug last year, leaving the door open to rookie Chase Roullier to impress at center. The Redskins seem content with Roullier at center, so if they brought back Long, they¡¯d have to shift one of them to guard ¡ª and they could also decide to save some money by letting Long walk.

High-level target: Andrew Norwell, Panthers

Norwell is very much a big mauler in terms of his play style. He has a huge frame at 6-foot-6, 325 pounds that is more in line with a typical offensive tackle¡¯s frame than a guard. But Norwell plays inside and has a nasty streak to his game.

On this play, Norwell aligns at left guard and has a defensive tackle lined up over his inside shoulder. His job on this run is simply to block down on that defensive tackle and pin him inside.

Norwell gets a little help from his left tackle, who gives him a push for added momentum. But Norwell makes the most of that, taking the defensive tackle and driving him completely out of the play. He shows his nasty streak, too, fully finishing the block to the ground.

His physical style and desire to finish blocks shows up in his pass protection, too.

At left guard again, Norwell cuts off the defensive tackle trying to work across his face into the A gap. The tackle then attempts to bull rush Norwell back into the quarterback, but Norwell gets his hands inside and takes over the block, driving the tackle to the ground and giving his quarterback plenty of time to throw.

Norwell is just 26 and is likely to be the top guard available on the market. His age makes him likely to live out the life of a long-term contract, but because of that and his talent, he¡¯ll likely be expensive. With Trent Williams and Morgan Moses already on expensive contracts and Brandon Scherff¡¯s contract renewal due soon, would the Redskins want to add another expensive contract to the offensive line?

Under-the-radar target: Zach Fulton, Chiefs

Fulton has been the perfect utility lineman for the Chiefs. This season, he filled in across all three interior positions for Kansas City, playing center against the Redskins, left guard against the Giants and right guard against the Broncos. He performed well at each spot and was solid in both run and pass protection.

Here, Fulton lines up at center and works against Redskins defensive lineman Ziggy Hood. The Chiefs run a zone play to the right.

Fulton does a terrific job getting Hood to work across his face toward the play side of the run. From there, Fulton drives him back and washes him out of the play, creating a big lane for the running back to work with behind him.

Fulton, like Norwell, is only 26, meaning he¡¯s not on the downturn of his career. His versatility is a huge string to his bow, being able to fill in at any of the three interior spots at a competent level. He¡¯s coming off a solid season with the Chiefs and could be a good under-the-radar pickup if Washington opted to pursue him.