The good: The Lions were humming along nicely at the beginning of the season upfront on defense.

Fifth-year defensive end Ziggy Ansah showed out Week 2 in New York on Monday Night Football with three sacks in a Detroit victory over the Giants.

Detroit was very good stopping the run through the first month of the season before defensive run stopper Haloti Ngata was lost for the year. Through the first five weeks of the season, only Atlanta in Week 3 managed to gain more than 100 yards on the ground. After Ngata was injured, Detroit struggled to stop the run.

There were also some good individual performances upfront for Detroit.

Ziggy Ansah recorded double-digit sacks (12.0) for the second time in his career.

Anthony Zettel proved he could be a productive player in year two with 6.5 sacks and 11 tackles for loss.

A'Shawn Robinson was much more productive in his second season at defensive tackle. He improved his total tackles to 53 this year after having 30 as a rookie. He also defended six passes – he now has 13 in two seasons – and recorded his first interception and touchdown.

The bad: Things got off on a sour note in August when Kerry Hyder Jr. was lost for the season in the first quarter of Detroit's first preseason game in Indianapolis due to an Achilles Injury. Hyder, who was coming off an eight-sack performance the year prior, was expected to play a big role along Detroit's defensive front this season.

We already mentioned the Ngata injury, which was a big blow to the middle of the defensive front. After he was lost for the year, the Lions gave up at least 100 yards rushing to eight of their remaining 11 opponents.

Knee and back injuries zapped Ansah's effectiveness for a stretch in the middle of the season, forcing him to miss games vs. Cleveland and Chicago Weeks 10 and 11.

The injuries and shuffling around led to a lot of inconsistencies upfront for the Lions' defensive line this season. It seemed like it was either feast or famine for that unit a lot of times this year.

The Lions' 35 sacks ranked 20th. Their 168 total quarterback hurries, per Pro Football Focus stats, were just the 24th most among the league's 32 teams.

Defensively, the Lions finished 21st in points allowed (23.5), 27th overall (355.8), 27th against the pass (243.2) and 18th against the run (112.5).  Those are stats all three phases of the defense have to own – defensive line, linebackers and secondary – but everything starts upfront.

The Lions have to be better on a consistent basis upfront in 2018.

Key stat: STATS INC.'s "Protection Index" is a statistic that measures offensive line play using different statistical elements like passing attempts and yards (excluding yards after the catch), sacks, quarterback knockdowns, hurries and penalties, including holding and false starts to form a numerical index assigned to each team. 

Looking at the combined Protection Index of opposing offensive lines when playing the Lions, it also gives us a good idea of the overall disruptiveness of Detroit's defensive line this season. The Lions ranked just 24th in opponent index this season.

Free agents: Ziggy Ansah (unrestricted), Haloti Ngata (unrestricted), Dwight Freeney (unrestricted), Jordan Hill (unrestricted), Brandon Copeland (restricted), Kerry Hyder Jr. (exclusive rights), Christian Ringo (exclusive rights), Rodney Coe (exclusive rights).

Obviously the two biggest decisions here for the new coaching staff will be how Ansah and Ngata fit into the future plans on defense, if at all. The new scheme and playing style will be factors in those decisions.

Ansah is going to be one of the more sought after free agents on the market, unless the Lions keep him off the open market by re-signing or tagging him.

With Ngata in the lineup the first five games of the season, Detroit's defense allowed an average 74.6 yards per game on the ground. After he was lost for the rest of the year with a torn bicep, that number ballooned to 114 yards per game. He appears to have something left in the tank at age 33 (turns 34 Jan. 21), and has indicated he wants to return for another season.

Hyder said he'll be back and better than ever next season coming off an Achilles injury.

Draft: There are some good pass rushers in this draft, and it's also a class very deep at defensive tackle. Those are both needs for the Lions at this point in the offseason.

In terms of edge rushers, NC State's Bradley Chubb heads the class and is a likely top 10 pick. Then there's guys like Arden Key (LSU), Christian Wilkins* (Clemson), Clelin Ferrell* (Clemson), Sam Hubbard (Ohio State) and Josh Sweat (Florida State), who are all listed as "outstanding" prospects and among the best 55 players available by Scouts Inc.

Early estimates have this year's draft class strongest at running back, defensive tackle and in the secondary.

Michigan's Mo Hurst leads a very solid crop of defensive tackles, followed by Derrick Nnadi* (Florida State), Vita Vea (Washington), Dre'Mont Jones* (Ohio State) and Da'Ron Payne* (Alabama).

*underclassman who haven't declared for draft yet (Jan. 15 deadline)

MVP: A lot has been made of Ansah recording nine of his 12 sacks this season in just three games, but his dominant performance helped the Lions win two of those games (New York and Green Bay). His 15 tackles for loss, which were spread throughout the season, ranked in the top 10 in the NFL.

Ansah was still able to be productive despite dealing with nagging injuries all season long. When he felt the best he had all year at the end of the season, he was dominant.

Most improved: Second-year defensive end Anthony Zettel was forced into a bigger role when Hyder went down with an injury. Zettel had already been impressing Lions coaches with the way he attacked the offseason with some former Penn State teammates and transformed his body to be better prepared for the rigors of an NFL season. Zettel embraced the bigger role and finished with 6.5 sacks, 11 tackles for loss and 31 quarterback hurries.

Quotable: "I think if I finished the year healthy I would have been a little closer to probably retiring, but I want to finish the season, so I think I want to keep on playing," Ngata told 97.1 The Ticket.

"I loved being able to be here and help Detroit have more dominance in this league. We've had winning seasons, and I just want to continue to build this franchise and get it to where it can be a dominant franchise and a great team, so I definitely want to be here. I definitely want to keep on playing, but we'll have to see once free agency hits."