The good: This was a Detroit Lions linebacker group in transition this season. After releasing veteran DeAndre Levy in March and drafting Jarrad Davis a little under two months later, the Lions ushered in a new era at linebacker.

Couple that with the drafting of Jalen Reeves-Maybin in the fourth round, and the Lions went considerably younger at the position in 2017.

Davis had his ups and downs like all rookies do, but he brought a physical presence to the defense, especially in the run game, that they didn't have before he arrived. He was playing his best football at the end of the season, which is a good sign for any rookie heading into their second year. Davis recorded 12 tackles and notched his first career interception in Detroit's Week 17 win over Green Bay. He finished the season with 96 tackles, two sacks, a forced fumble and an interception in 14 games.

Veteran Tahir Whitehead recorded another 100-tackle season (110), giving him back-to-back 100-tackle performances (132 in 2016). He was second in the NFL with four fumble recoveries.

Reeves-Maybin saw his playing time increase toward the end of the year. One thing that stuck out about him was his speed. He can fly around and make plays. At only 230 pounds, he needs to continue to add muscle and bulk to his frame, however.

The bad: This is a Lions' defense that didn't rank in the top half in the NFL in any major statistical category. Detroit finished 27th overall defensively.

Fitting gaps and stopping the run were certainly issues at times this season. Nine times this season the Lions allowed opponents to gain more than 100 yards on the ground. That included 222 yards to Chicago, 201 yards to Cleveland, 193 yards to New Orleans and 151 yards to Atlanta Week 3.

Another area where this linebacking corps really seemed to struggle at times was in coverage. Opposing passers had a 102.9 passer rating with three touchdowns throwing on Whitehead.

When throwing Davis' way, the opposition's passer rating was 106.5 with two scores. At one point in the season, Davis was being taken off the field on obvious passing downs because of his struggles in that department.

Veteran Paul Worrilow, who started eight games and was a key reserve in five others, allowed three touchdowns in his coverage with a 132.9 passer rating.

That's one area the new coach on defense will have to address.

Key stat: Detroit was 1-2 this season when allowing an opposing quarterback to pass for 300 yards. They were 1-3 when an opposing running back gained at least 100 yards on the ground.

Free agents: Tahir Whitehead (unrestricted), Paul Worrilow (unrestricted) and Nick Bellore (unrestricted).

Whitehead handled the move from the MIKE to the WILL like a pro after the team drafted Davis to be the MIKE of the future. Whitehead has some strengths and weaknesses to his game, like all players, but if anything, he's proven to be productive and versatile. The Lions will likely want to get Reeves-Maybin on the field more moving forward, so we'll see how that might impact Whitehead's future.

Bellore was a core special teamer and used as a fullback in certain spots. He even caught a touchdown pass.

One thing to keep in mind here is that there's likely going to be a change in scheme next season with the new coaching staff. Teryl Austin, who was Detroit's defensive coordinator the last four years, has left to take a similar role in Cincinnati. Who knows, maybe a shift to a 3-4 scheme could be coming, depending on the new coaching staff's preference. That will certainly effect the status of both the numbers at linebacker and what roles players might have.

Draft: Without knowing Detroit's defensive scheme next season, it's probably prudent to include linebackers that project to both a 4-3 and 3-4 at the NFL level.

Boston College's Harold Landry is the highest graded linebacker by Scouts Inc. in this year's draft. He's projected as a best fit in a 3-4.

Georgia's Roquan Smith is probably the most versatile linebacker of the bunch. His speed, instincts and strength should allow him to play both inside or outside at the next level.

Some other linebackers to keep an eye on are Tremaine Edmunds (Virginia Tech), Rashaan Evans (Alabama), Malik Jefferson (Texas) and Lorenzo Carter (Clemson).

MVP: Whitehead may have had some struggles in coverage, but he was pretty darn good against the run as an individual. In fact, he earned the third-highest grade against the run by Pro Football Focus among all 4-3 outside linebackers.

He led the team in tackles for a second consecutive season, and also notched an interception, a sack and recovered four fumbles. He also played and started in all 16 games.

Most improved: The fact that Davis was playing his best football toward the end of the season speaks to his ability to prepare, learn and adapt to coaching. Experience is the best coach in this league, and Davis steadily got better as the year progressed.

His 96 tackles ranked first among all NFL rookie and first-year players in 2017.

He's a natural leader with terrific communication skills. Those were things that already stood out when he got to Detroit. It's written all the time, but a player's biggest jump usually comes in year two. Now that Davis has seen just about everything, and is afforded a true offseason to rest his body and prepare for his second season, expectations should be high for him.

He's likely going to have to learn a new scheme, but that shouldn't be too difficult for a player as smart as Davis.

Quotable: "I think on defense we need to add some pieces," Lions general manager Bob Quinn said after the season.

"I think I need to do a better job on that side of the ball and there's some guys that are under contract that'll be coming back, so hopefully those guys develop. I think that's the key thing too, is younger players in their second and third year have to show improvement. So, you can't be stagnant. You got to keep moving forward and I think player development's a big thing for us."