BOURBONNAIS, Ill. -- Rod Marinelli, the gruff ex-Marine tunnel rat, loves the smell of a man's breath in the late afternoon.
It smells like ... victory.
"Believe me," he said of the competition on his stacked defensive line. "They're all breathing on each other's neck, which you like."
Competition breeds competitive players.
Marinelli's unit, the Fighting 4-3, is locked and loaded with a promising rotation of interior linemen to go along with three solid to spectacular defensive ends, veteran linebackers and an aggressive secondary.
While most of the starting positions are locked up, the competition is ripe in other places, like the interior of the defensive line.
"So far I've seen it," Marinelli said of the depth at the inside line spots. "We'll put them under fire a little more and we'll see if we continue to see it. I like the battles that are going on."
"It's great," defensive end Corey Wootton said. "Because guys are competing every day and it's really why guys are doing so well. Competition pushes people and I really think it's pushing the defensive line."
It's a friendly competition for playing time right now among the half-dozen interior linemen vying for major rotation time, and most believe the depth on the front four will allow the coaches a broader rotation, and thus, fresher legs.
"We all feed off each other," defensive tackle Henry Melton said. "We're all rooting for each other because we don't want any drop-offs. We want everyone playing at a high level.
"It's fun when we go out there, because everyone's competing," he continued. "When you look at film, there are a lot of resemblances between a lot of other guys in the team. Everybody can pretty much go in there and get the job done. It's basically who can go in and be the playmaker."
It was obvious when he joined the team two seasons ago as defensive line coach that the Bears love Marinelli for his candor and his detail-oriented style.
As a first-year defensive coordinator last season, he helped the Bears rebound from a post-Super Bowl malaise and spring back to league dominance. Simply put, he is the perfect leader for this group and the best thing to happen to this defense in years, including the addition of Julius Peppers.
"He's hard-nosed, old-school guy," Melton said. "He wants things done the right way -- perfect -- and you don't want to disappoint him."
Lovie Smith likes to correct reporters who give Mike Martz ownership of the offense. And it's getting to the point where we shouldn't be crediting the defense to Lovie either. Marinelli isn't looking for credit though.
"The whole defense is built on trust, coaches and players together," Marinelli said. "The coaches know every coach is coaching the exact same thing. All the details show up. That's what you're looking for; that you can trust a guy and they can trust each other."
Through the early part of camp, most of the questions have been about the unproven offense thus far. Can Jay Cutler shake off his last game? Can Martz's system work? Can the offensive line hold up? What's up with Johnny Knox and Roy Williams? Will Matt Forte get his new paper?
The defense, the standard-carrier for this franchise, has just gone about its business. Aside from Tommie Harris and Danieal Manning departing, there hasn't been much turnover.
"It's OK that we're not getting a lot of attention right now," Lance Briggs said. "We'll get attention when we get on that field."
Before camp started I had a premonition that the offense would improve and the defense would regress. This vision came from me trying to expect the unexpected, which is a logistical nightmare in and of itself.
Now I'm back to reality. This is the Chicago Bears after all. I think the defense is going pick up right where it left off last year, a lockdown second-half team.
The Bears' depth up front is exciting everyone at camp, especially the guys playing behind them.
"We've got D-line for days on the interior," safety Chris Harris said. "You got Anthony Adams, Henry Melton, Matt Toeaina, all these guys are starting-caliber tackles. And then you throw in the rookie [Stephen] Paea and they just added Amobi Okoye. They should be extremely fresh so I'm hoping to see a lot of sacks, a lot of pressure out of them, which will create turnovers and interceptions on back end for us."
He left out Marcus Harrison too. After conquering the battle of the bulge, Harrison was working with the second team in practice Thursday.
Okoye, the former first-round pick of the Texans, is very promising, and Wootton is having a great camp by all accounts. With Harris gone, it'll be refreshing to see some young linemen rise up.
No one's quite sure how the rotations will look in the Bears' preseason opener Saturday against the Buffalo Bills at Soldier Field.
"I'm going to try to make it pretty equal, and let these guys really compete," Marinelli said. "These two-minute drills we do are fun. It can really tell you who can pass rush when they're fatigued, under duress, who can make calls and communicate. Those type of things. Those are all the things you're looking for."
Wootton, the second-year player from Northwestern, said he and Peppers and Toeaina, and the other subs, are champing at the bit to hit some guys this weekend.
"The biggest thing is focusing on technique and getting after the passer," Wootton said. "That's what Coach Marinelli really loves. We're rushmen, that's what he calls us."
While it's easy to be positive right now, Briggs, the wily veteran, is circumspect.
"Right now, everyone looks great in practice," he said. "We get tested this week and then we'll start evaluating. Coaches will evaluate and we'll evaluate ourselves on how we look as far as going into the season."
Jon Greenberg is a columnist for ESPNChicago.com.