Defense figures to be the Rams’ strong point for 2016

He’s been in the trenches.

As a defensive lineman for the only Rams team to win a Super Bowl, and a St. Louis radio broadcaster who watched the franchise struggle through an 11-year playoff drought, D’Marco Farr can recount the team’s problem areas through the years.

The defense, as the Rams return to Los Angeles, is not one of them.

“If the quarterback position was solidified, this defense is good enough for the Rams to compete with the big boys of the NFC,” said Farr, who works as an analyst on Rams’ games and played for the club in Los Angeles before its move to St. Louis.

When the Rams open the 2016 season, the defense will be the strength for a team seeking its first winning season since 2003.

Tackle Aaron Donald, a two-time Pro Bowl pick, is the star of an aggressive unit deployed by coordinator Gregg Williams in a 4-3 scheme.

Despite losing outside linebacker Alec Ogletree, end Robert Quinn and safety T.J. McDonald because of injuries, the Rams ranked 10th in total defense, 10th against the pass and 13th against the run.

“The cumulative effect of losing them probably caused our defense to go from being dominant to just good,” General Manager Les Snead said.

The defense played well in early-season NFC West victories over Seattle, Arizona and San Francisco.

It is a unit that held Pittsburgh to 12 points in a home loss, limited Baltimore and San Francisco to fewer than 20 points in road losses, and ended Green Bay quarterback Aaron Rodgers’ streak of 587 passes without an interception at Lambeau Field.

Farr described the defense as “playoff ready.”

Coach Jeff Fisher sounded confident.

“I think I have the defensive MVP in Aaron Donald up front,” he said. “We have some DBs we have to re-sign but we’re going to be solid.”

Snead’s challenge will be keeping the defense intact.

Starting cornerbacks Janoris Jenkins and Trumaine Johnson, linebacker/safety Mark Barron, safety Rodney McLeod and ends William Hayes and Eugene Sims are set to become free agents.

Snead said the Rams must continue to build — and not slip back.

“When something is your strength,” he said, “keep adding fuel to that fire.”

A look at the defense, which ranked sixth in third-down situations and 11th in sacks, as it stands now:

Defensive line

The 6-foot-1, 285-pound Donald is the force for a deep and talented position group that helped produce 41 sacks.

Donald, the 13th overall pick in the 2014 draft, had a team-best 22 tackles for loss, including 11 sacks.

At 6-5 and 326 pounds, nose tackle Michael Brockers plugs the middle and frees Donald and the ends to pressure passers.

Veteran ends Chris Long and Quinn, once regarded as dynamic pass-rushing bookends, are expected to return from injuries that sidelined them for stretches. Production by both slipped — Long had three sacks, Quinn five. Long might have to restructure his contract to remain with the team.

Hayes and the 6-foot-6 Sims stepped up to fill the void at end and performed well. Tackle Nick Fairley, a former No. 1 draft pick from Auburn, and Ethan Westbrooks are other linemen.

Linebackers

Middle linebacker James Laurinaitis is the cornerstone for a unit that also features Ogletree, former UCLA standout Akeem Ayers and hybrid safety Barron.

Laurinaitis, a seven-year veteran who has started 112 consecutive games, had 109 tackles and became the franchise’s all-time leader in that category.

Ogletree, a 2013 first-round draft pick from Georgia, was off to a fast start before suffering a season-ending ankle injury in the fourth game. He still finished 12th on the team with 42 tackles.

Barron moved into the lineup after McDonald suffered an injury and finished with a team-best 116 tackles.

Secondary

Re-signing Jenkins and Johnson is a priority after the cornerbacks combined for 10 of the Rams’ 13 interceptions.

Jenkins, the most experienced starter in the secondary, intercepted three passes. Johnson tied for second in the NFL with a team-best seven, and returned one for a touchdown.

McDonald is due to return from shoulder surgery and McLeod is coming off a 106-tackle season. Safety Maurice Alexander and cornerbacks Lamarcus Joyner and Marcus Roberson provide depth.

Special teams

Punter Johnny Hekker was selected to the Pro Bowl for the second time in three years.

Thanks to the Rams’ league-worst offense, Hekker attempted an NFL-high 96 kicks. He averaged a league-best 47.9 yards, and also led the league in net average (43.7) and kicks downed inside the 20-yard line (41).

Receiver Bradley Marquez and safety Cody Davis are special teams standouts for a kick-off coverage unit that ranked 11th, giving up 22.4 yards per return, and a punt coverage unit that ranked 13th (7.2 yards).

gary.klein@latimes.com

Twitter: @latimesklein