Bears coach Lovie Smith has told us for years his defensive scheme is designed to limit big plays. Well, chew on this, Lovie: The Bears gave up 17 plays of 15 yards or more and 12 plays of 20 yards or more during Sunday's extremely fortunate 34-29 victory over the Carolina Panthers.

The Panthers moved the ball at will on the Bears' defense all afternoon and piled up a whopping 543 yards. In case you were wondering, the Bears haven't given up that kind of yardage since this game in December, 1982. (Remember Vince Ferragamo?)

Yes, the Bears won -- thanks to an interception return for touchdown by D.J. Moore and a punt return for touchdown by Devin Hester. You can't count on those big plays every week. Smith has to get his defense fixed because it's bad right now -- real bad.

Worst of all, it isn't just the pass defense. The Bears are getting shredded on the ground.

The Bears are ranked 31st out of 32 teams in total defense. They allow 426 yards per game. The Panthers totaled 169 yards rushing on 26 carries Sunday, which leaves the Bears 24th in the league in run defense. They allow 124 yards rushing per game and 5.1 yards per rush -- a figure that ranks 28th in the league.

So, what's the problem, Lovie?

''We're working on that,'' Smith said at his Monday press conference at Halas Hall. ''Can't give you a reason why. Believe me, if we knew that, we wouldn't let it happen. But when things aren't working exactly the way we like, we go back to the practice field, we identify it, which we have, and we'll work to get it better.''

The Bears need to get better fast because they face a Monday night game against the undefeated Detroit Lions next week. The Green Bay Packers are also 4-0, which means the 2-2 Bears are already two games off the pace with two teams to catch in the NFC North.

There isn't much room for error if the Bears want to return to the playoffs this year. Right now, the Bears look nothing like a playoff team -- on either side of the ball.