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

Prior reviews: Quarterbacks; Running backs; Wide receivers; Tight ends; Offensive line; Defensive line; Linebackers

What has worked: Louis Delmas and Glover Quin, playing together for the first time, have been an effective safety tandem as the Lions' last line of defense. Last week against Dallas was not their best showing -- both of Dez Bryant’s touchdowns came when it appeared coverage rolling over was late -- but otherwise they have been playmakers in both the run and the pass.

Delmas is having the most consistent season of his career, and a lot of that has to do with the addition of Quin, who provides balance and steadiness to his athleticism and emotional play. Detroit’s defense is better with Delmas on the field because he is its emotional center.

The guys Delmas and Quin work with -- the cornerbacks -- have mostly been average. All three of the main corners, Rashean Mathis, Chris Houston and Darius Slay, along with nickelback Bill Bentley, have shown flashes of strong play, but they've had their struggles as well. Signing Mathis before the season looks to have been a good decision, as he has provided veteran stability and mentorship.

What has not: Cornerback consistency.

Detroit does not have a lockdown cornerback. Houston showed flashes of it, but then he struggled against the double moves of A.J. Green, was benched briefly and then spent much of the game against Dallas not matched up on Bryant.

Slay showed potential in the preseason and has been coming on stronger over the past few games, but he was beaten badly on a 60-yard touchdown against Dallas and is still clearly the Lions’ third cornerback. He is, though, probably the Lions' best corner for the future.

Mathis, while no longer as his Pro Bowl level, has been Detroit’s most consistent cornerback when he’s healthy. That’s the issue. He has played in every game and started the past six contests in place of Slay, but missed part of the Chicago, Cleveland and Cincinnati games due to injuries.

Bentley, playing the nickel, has also had consistency issues. He was in rough shape against Arizona, but played well in spurts against Green Bay and Cleveland. Still a second-year player, he is learning a lot.

As with the rest of the defense, stopping the run and the big play have been a concern. The Lions have given up 19 rushing plays of 10 yards or more this season, including a 67-yard rush by Green Bay wide receiver Randall Cobb and a 45-yard run by Cleveland receiver Travis Benjamin.

Prognosis: As long as Delmas’ knees hold up -- he has missed three plays over eight games and has generally felt healthy -- the Lions should be fine at safety. Quin and Delmas are both playing at a high level and have good communication with one another.

Detroit did not make a move for a cornerback at the trade deadline, so it will have to hope to get an improving Slay and Bentley, more consistent Houston and healthy Mathis for the second half of the season.

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