Lions coach Jim Schwartz had a Football 101 discussion about his defense the other day with beat writers. It's nothing you wouldn't garner from a little bit of film study, but for those who didn't follow the Titans closely in recent years here's a glimpse of how things might work in Detroit:

Schwartz said everything the Lions do “will be based out of 4-3 personnel, but we will have 3-4 principles within our” defense. In Tennessee, for instance, the Titans often played an odd front in nickel situations with three down linemen, three linebackers and five defensive backs (the Lions were mostly a 4-2-5 nickel team under Rod Marinelli). That allowed them to use stand-up pass rushers like Antwan Odom and Travis LaBoy as a third linebacker and rush from all over the field.

If the Lions use a similar configuration, newly-acquired Julian Peterson likely will be the stand-up rusher while ends like Cliff Avril and Dewayne White keep their hands on the ground. Peterson had 24 ½ sacks the last three years in Seattle.

“Our base was a 4-3 (in Tennessee), but we ran just enough (3-4) to make you prepare for it,” Schwartz said. “I know from talking to a lot of offensive coordinators it spreads them thin. The only way you can do it is if you have those kind of guys. Cliff's one, Julian's one. We had that with Antwan and Travis.”

The Titans also sought versatile players, as the Lions are doing now, to play left- and right-outside linebacker rather than weak- or strong-side. Ditto at safety, where there's no free or strong safety designation, just two interchangeable players.

“We sort of got away (from WILL and SAM linebackers) because we saw so many shifting teams and teams get out of shifting real quick if they're moving four people and you got all these guys on defense going, are you ready yet?” Schwartz said. “But if they're moving one guy and you're flipping four, they'll just do it 60 snaps a game.

“That's why you start getting a little less compartmentalized with SAM and WILL, strong safety and free safety. If you're a strong safety and you line up to the tight-end side and that tight end motions across, you can't flip because you don't know if he's going to stop and come back and if he does you're looking bad. Guess what, if you have a 230-pound strong safety that's an in-the-box strong safety you can turn him into the free safety just motioning one guy across the formation. So it puts more (emphasis) on having multidimensional (guys).”

The trick now, of course, is for the Lions to find those type of players. Tennessee's defense worked because it had Odom and LaBoy, plus a dominating three-down tackle in Albert Haynesworth and mirror linebackers Keith Bulluck and David Thornton. The Lions don't have an every-down tackle on their roster, don't know who their starting safeties will be and don't presently have a middle linebacker on their roster.

All that considered, that's why I believe the Lions, even after the Peterson acquisition, are still considering Aaron Curry with the No. 1 pick. Curry is a multidimensional player who probably projects best as an outside linebacker, maybe in the Peterson mold with fewer sacks but better coverage skills. The Lions are building long-term, Peterson's contract is such that he won't be here but a year or two, and Curry would fill a gaping hole at middle linebacker in the interim.

Asked who his middle linebacker is as of today, Schwartz didn't have a firm answer.

“At some point we're going to have to put some pads on and some mouthpieces in and that's part of the job description for a middle linebacker,” he said. “You're going to see who can go thump, and we might not have a feel for that until training camp. I mean, who really can thump. You might think a guy can, but (you don't know) until you see it in training camp when the shoulder pads come on and that mouthpiece goes in.”