Part 6 of an 11-part review of the 2017 Bears season.

All of the success the 2017 Bears accomplished on defense started in the trenches.

General manager Ryan Pace’s successful investments in the defensive line have paid off and provide a foundation for success moving forward, especially with the decision by defensive coordinator Vic Fangio to return with new head coach Matt Nagy. That’s not to overlook the fine work done by defensive line coach Jay Rodgers, who was a priority to bring back on the new staff.

The Bears finished 10th in total defense (319.1 yards per game), 11th against the run (108.1 yards), seventh against the pass (211.0 yards) and ninth in points allowed (20.0), keeping them in most of their games.

The defense did not allow a 100-yard rusher until the season finale when the Vikings’ Latavius Murray ran for 111 yards. The Bears encountered a fine list of running backs during the season, including Le’Veon Bell, Mark Ingram, Alex Collins, Carlos Hyde and Alvin Kamara. All finished in the top 15 in rushing, except for Kamara, the offensive rookie of the year for the Saints.

The Bears managed to finish tied for seventh with 42 sacks, and that was despite having only one player in the top 25 in the category — defensive end Akiem Hicks, who tied for 25th with 8 1/2. The consistent pressure provided by the line generated opportunities for many players to get involved in the pass rush and produce results despite the absence of a dominant edge threat for parts of the season.

It all added up to make the defensive line the strongest position group for the Bears in 2017, and if a new head coach is going to take over, that’s not a bad place for the strength of the roster to be.

Roll call: Akiem Hicks (signed through 2021), Eddie Goldman (signed through 2018), Mitch Unrein (unrestricted free agent), Jonathan Bullard (signed through 2019), Roy Robertson-Harris (signed through 2018), John Jenkins (unrestricted free agent), Rashaad Coward (signed through 2018).

A look at key members of Matt Nagy's Bears coaching staff for 2018.

2018 salary-cap figures: Hicks $9.6 million, Goldman $1,809,283, Bullard $924,360, Robertson-Harris $557,334, Coward $555,000.

2017 season review: The Bears ponied up before the season kicked off by extending the contract of Hicks with a four-year, $48 million extension. Hicks believed he was a $10 million per-year player (or more) when he signed a two-year deal to join the Bears in 2016, a contract that was for $10 million over two years. On the Saturday before the season opener, Hicks’ deal was finalized, guaranteeing him $22 million fully and $30 million against injury. There was moderate risk when Hicks was signed to his third team in less than a year and the Bears believed he was an ascending player entering his prime who would be even better in their scheme. That proved to be true and by signing him when they did, the Bears surely got Hicks for a slightly lower price than they would have been forced to pay if he had played out the deal. In all likelihood, they would have used the franchise tag on Hicks, but that is a moot point now with him under contract through 2021.

Hicks was a consistent force against the pass and run. He led the team with 41 1/2 quarterback knockdowns and hits, tying for 30th. The leader was the Cowboys’ Demarcus Lawrence (75) followed by the Rams’ Aaron Donald (70 1/2), who was voted the NFL defensive player of the year. He celebrated his new contract with three quarterback hits and two sacks in the opener against the Falcons and was consistent throughout the season, even though he had seven sacks at the midway point of the season and added just 1 1/2 in the final eight. Hicks was still in the backfield down the stretch with nine quarterback hits in the final nine games, the sacks just didn’t happen. He finished sixth on the roster with 54 tackles, according to press box statistics, a figure I suspect is higher in the totals the team keeps but no longer makes public.

Hicks’ value cannot be overstated because he has proved to be an absolute workhorse. He finished the season with 899 snaps, meaning he was on the field for 85 percent of the defensive snaps, putting him in elite company as he ranked fourth among all defensive linemen in snap percentage behind only Cameron Jordan, Jason Pierre-Paul and Khalil Mack. That’s good company. Hicks was on the field for all 66 snaps in the Week 9 game against the Packers, the middle part of a three-game stretch in which he missed only four snaps. Truth be told, the Bears would probably like to reduce Hicks’ workload slightly in order to keep him fresher late in the game and in the latter parts of the season.

As valuable as Hicks was, Goldman was just as good for the defense. That’s important to consider as extending the contract of the second-round pick from 2015 will be an offseason priority for Pace. Goldman was able to play in 15 games, missing only the Week 14 game in Cincinnati with a hip issue, and that was paramount after he missed 10 games in 2016, primarily hampered by a high ankle sprain. Goldman graded out tops on the defensive line by coaches, and while nose tackles are never going to amass big statistics, Goldman’s value cannot be understated. He remains young as he turned 24 last month and has proved that he can remain in good shape, something that was a question when he first arrived. What kind of payday can Goldman expect? It’s a little early to speculate and the Bears certainly will prioritize free agency and the draft first, but the Ravens made Brandon Williams the highest-paid nose tackle in the league last March with a five-year, $52.5 million contract. Williams was 28 when the deal was consummated, but it’s important to note he was days away from becoming an unrestricted free agent when the deal was struck. Goldman has one year remaining on his rookie contract and the only way he can maximize his value is to play out that deal. Goldman’s 44 tackles ranked ninth and he has 1 1/2 sacks and five quarterback hits and is the lynchpin of the run defense. Goldman was second on the line in play time with 609 snaps (57.6 percent).