In the 2013 season, when the Seattle Seahawks won their first Super Bowl title in franchise history, their defensive line was so stacked that future Pro Bowlers Michael Bennett and Cliff Avril came off the bench. Seattle's star-studded secondary received much of the attention -- rightfully so -- but the defense that led the NFL in takeaways with a whopping 39 started with the big boys up front.

The 2017 version can be even better with the addition of Sheldon Richardson via a trade with the Jets on Friday.

Richardson strengthens what was already a dominant defensive line, and he gives the Seahawks the interior presence they hoped they were getting with top pick Malik McDowell, who may miss his rookie season and possibly beyond following a serious ATV accident.

Richardson has 18 sacks over four seasons, which is a significant total for a pass-rusher whose natural position is 3-technique defensive tackle. That includes 3.5 sacks en route to being named the NFL's Defensive Rookie of the Year in 2013, then eight in 2014, when he was named to the Pro Bowl after his most productive season. He could be a starter in Seattle's base packages depending on what happens with Ahtyba Rubin, but Richardson's presence in Seattle's nickel pass-rush will make that foursome arguably the NFL's best.

Good luck blocking Avril, Bennett, Richardson and Frank Clark.

Richardson has 18 sacks over four seasons, which is a significant total for a pass-rusher whose natural position is as a 3-technique defensive tackle. Kelley L Cox/USA TODAY Sports

The Seahawks were tied for third in the NFL in sacks last season with 42. That was despite Bennett's missing five games with an injury. It also was despite the Seahawks' sending an additional (fifth) pass-rusher on only 25.5 percent of their defensive snaps. According to ESPN Stats & Information, that percentage was 20th in the league, which is an indication of how effective Seattle was at generating pressure with its front four.

Avril posted a career-best 11.5 sacks last season to lead the team. Clark was second with 10. Bennett is one of the NFL's most disruptive defensive linemen even if his sack totals don't show it.

And that group just got even better, as did Seattle's defense as a whole. That group now features eight players who have made a Pro Bowl: Richardson, Bennett, Avril, linebackers Bobby Wagner and K.J. Wright, cornerback Richard Sherman, and safeties Earl Thomas and Kam Chancellor. One exception is Clark, who's loaded with potential.

Richardson isn't a perfect addition on the field or off of it. He's coming off what by his standards is a down season with 1.5 sacks in 15 games, though he did play some outside linebacker and still was effective. He also has been suspended twice, first for a violation of the NFL's substance-abuse policy and then following an arrest related to a high-speed car chase with police in 2015. His act apparently wore thin on Jets coach Todd Bowles.

Richardson may be difficult for the Seahawks to re-sign when his contract expires after the season given all the money Seattle is committing to its other stars. According to Spotrac.com, the Seahawks have eight players whose contracts average at least $10 million, topped by quarterback Russell Wilson at $21.9 million. But Richardson's effort has never been a question and he should be especially motivated in a contract year.

The Seahawks have seen how far a dominant defensive line can take them. Theirs just got even more dominant with the addition of Richardson.

Information from ESPN Jets reporter Rich Cimini was used in this report.