This week, during Detroit’s bye, we’ll take a look at each position group at the halfway point of the season.

Prior reviews: Quarterbacks; Running backs; Wide Receivers; Tight ends; Offensive line

What has worked: It is kind of a strange deal this season for the Detroit defensive line. The numbers aren’t there as far as sack totals, but the Lions' front four has been one of the more disruptive in the NFL.

Detroit’s front four is asked to do a lot more than other front fours in the NFL. The Lions rarely blitz, so it is on the four players up front to force almost all of the pressure Detroit is able to bring and as mentioned above, while the numbers don’t reflect it, the Lions have done well there.

According to Pro Football Focus, Ndamukong Suh leads all defensive tackles in quarterback hurries with 31 and has been the second-best defensive tackle in the league rushing the passer along with the sixth-best tackle overall.

Willie Young is also having a productive season in his first time playing a lot of snaps. He’s rated as the 16th-best 4-3 defensive end in the league by Pro Football Focus but also is fourth in quarterback hurries with 25.

When he has been healthy, Nick Fairley has been productive, including Sunday against Dallas when he hit quarterback Tony Romo three times. Ziggy Ansah has been similar. When healthy, he has been better than the Lions could have expected as a first-round pick who still was very raw.

The Lions’ other defensive line pick, Devin Taylor, doesn’t play much but has shown potential. Taylor helped force a holding call against Dallas last Sunday and in 89 snaps on the season he has eight tackles, a sack and a forced fumble.

What has not: This has to start with Suh’s fines. Although the fine for the hit to QB Brandon Weeden was questionable, Suh has amassed $131,500 in fines the past two months and there’s always a chance that the next time Suh does something questionable, he could get suspended instead of just losing more money.

The Lions can't complain about their lack of sack production out of their defensive linemen if they aren't going to blitz more often. The Lions are 15th in the league in sacks from defensive linemen with 11 -- and 3.5 of them came from Suh. The Lions are 15th in the league in sacks from defensive linemen with 11 -- and 3.5 of them came from Suh.

At some point, Detroit will have to start reaching the quarterback and bringing him down instead of just chasing him. The reasoning behind that is a sack is more of a negative play than a throwaway (not every pressure leads to an interception) and the more long second and third downs Detroit can force, the better it is for its back seven.

Another concern is rushing yards allowed. The Lions are 29th in the league in yards per rush allowed (4.74) and have been susceptible to giving up the big run -- notably to Adrian Peterson on the first defensive drive of the season and a 53-yard touchdown run by Chicago’s Matt Forte. As the season progresses, the Lions need to improve there and that starts with the defensive linemen.

Prognosis: It should be good. Detroit still has one of the most dominant linemen in football in Suh and the more he attracts double-teams, the more that opens up pass-rushing lanes for the rest of the defensive linemen.

They have also placed enough pressure on quarterbacks that eventually the law of averages would suggest they will start seeing actual sacks instead of pressures and throwaways.

But it is a good, talented and deep group that has to continue with its strong play -- stats or not -- for the Lions to have any sort of defensive success the second half of the season.

Information from ESPN Stats & Information was used in compiling this report.