Former NFL general manager has a lingering concern about Detroit Lions defense

This offseason, if the Detroit Lions were planning to take the next step during the 2023 season, the cornerback room had to be turned over, overhauled, upgraded, whatever label you like. General manager Brad Holmes got it done, signing Cameron Sutton, Emmanuel Moseley and the versatile safety/slot corner C.J. Gardner-Johnson before the first seven days of the free agency period was over.

Still, those new pieces in the secondary have to learn how to work together, and there will be no in-season ramp-up with the Kansas City Chiefs on the slate for Week 1. So there is a "we need to see it" element, even if we fully expect to see it.

The Lions had one game last season, against the Seattle Seahawks, where they did not force a punt. Overall, they allowed a 45.1 percent conversion rate on third down, 27th in the league. In concert with allowing less yardage, points, etc., getting off the field on third down better is critical for the Lions' defense.

Former NFL GM has lingering concern about Detroit Lions defense

Former NFL general manager Randy Mueller (subscription required) put together a list of biggest concerns for each team in the NFL North heading into the 2023 season. Here's what he said about the second of the two he had for the Lions.

"This won’t be a surprise to anyone, least of all to Lions fans, but the biggest concerns I have for this team are on defense. Per TruMedia, the Lions ranked 28th in scoring defense and 30th in getting off the field on third downs (allowing a 45 percent conversion rate). They allowed 5.2 yards per rush; only the Chargers were worse. All despite blitzing 33 percent of the time, which was sixth-highest in the league, in all likelihood to try and stop the bleeding."

- Randy Mueller, The Athletic

"Signing free-agent defensive backs Emmanuel Moseley and C.J. Gardner-Johnson to one-year deals doesn’t solve the issues long-term but it does get things back to even par... I know Detroit used a first-round pick on a linebacker (Iowa’s Jack Campbell), but I still worry about it being able to stop anyone in the near future — run or pass. At least it will be fun watching them try to outscore people, especially in this division."
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- Randy Mueller, The Athletic

TruMedia apparently tilts the Lions' same third down conversion rate allowed last year a few spots worse in their ranking, but the broad point stands. If there's one number that will reveal the Lions' defensive effectiveness this season, it will be the rate of third down conversions they allow. Everything else will flow to, and through, that number.