By Jim Thomas

Tough, aggressive and obsessed with the fundamentals. That's Mike Zimmer. But would you expect anything less from Bill Parcells' defensive coordinator?

Zimmer, 49, is the longest-tenured member of the Dallas coaching staff. He broke in with Barry Switzer in 1994 and has outlasted head coaches Switzer, Chan Gailey and Dave Campo in the Big D.

Parcells and club owner Jerry Jones liked Zimmer so much they persuaded him to stay with the Cowboys in 2004 when Zimmer had a chance to become head coach of the Nebraska Cornhuskers. In the process, Zimmer got a hefty pay raise to remain as defensive coordinator. He's believed to be making $1 million a year.

Zimmer could be due for another pay raise. He spent Thursday afternoon in Chicago being interviewed by team president John Shaw and president of football operations Jay Zygmunt for the Rams' head-coaching job.

Zimmer is the first candidate interviewed by the Rams; at this point Zimmer has no other interviews lined up for the eight head-coaching vacancies in the NFL.

Zimmer is the son of a football coach. His father, Bill, now retired, was a longtime coach at Lockport (Ill.) High. Mike spent a good chunk of his childhood attending his father's practices and watching film with his dad. When he got to high school, Mike played quarterback for his father.

Parcells admires the fact that Zimmer grew up in the game.

"Mike's a coach's son. He knows," Parcells told the Dallas Morning News. "Mike knows the deal. I'm not into this sensitivity (stuff). . . . Mike's good. I've always thought a lot of him. He works hard. He's feisty. That's OK. I like that in him. I really do."

Zimmer isn't into the sensitivity stuff, either. He can be loud and profane with his players when mistakes are made on the practice field. And if something isn't done right, he'll light into anyone - from the biggest star down to a practice squad player.

No matter how well the Cowboys' defense plays - and it has had three top 10 finishes in total defense in his five seasons as coordinator - Zimmer thinks it can always do better.

He routinely shows up for work at 4 a.m. In the past, one of his pet phrases to defensive players came in the form of a question: "What kind of guys do you like?"

According to the Fort Worth Star-Telegram, the player was supposed to immediately respond: "Tough guys."

Former Cowboys cornerback Mario Edwards once said Zimmer literally shamed him into becoming a better tackler, embarrassing him in front of the team.

But Zimmer is also about building unity and camaraderie. In training camp before the 2001 season, he asked players to report for a defensive team meeting. . . . and then showed them movies such as "Remember the Titans." Popcorn provided.

During that same 2001 camp, he designated a "leader of the day" for the defensive unit. That player would wear a yellow jersey that day, making it easier for teammates to watch his work ethic and attentiveness to detail in practice.

"As I've gotten to know Mike, I've grown to appreciate him," Parcells once told Cowboys reporters. "I see a lot of myself in Mike. He's a football guy, top to bottom. These are the guys I've always gravitated to. Football is very important to him.

"If there's anything I've encouraged Mike to do, it's be a little more patient with his evaluations. He's an 'I.E.' - Instant Evaluator. I'm going to change him."

Veteran Cowboys observers say Zimmer gets more freedom to run the defense by Parcells than assistant Sean Payton gets in running the offense. That being said, Parcells decided to switch to the 3-4 this year, a scheme Zimmer had never coached before in his career.

More interviewsscheduled

Shaw and Zygmunt are scheduled to interview two candidates today in Chicago: Bears defensive coordinator Ron Rivera and Miami offensive coordinator Scott Linehan. The only other visit currently scheduled is Giants defensive coordinator Tim Lewis on Monday in New York.

Mike Zimmer

Age: 49

Hometown: native of Peoria, Ill.; grew up in Lockport, Ill.

Coaching background: college assistant at Missouri (1979-80), Weber State (1981-88), Washington State (1989-93). NFL assistant at Dallas (1994-present), including five seasons as defensive coordinator.

Fast facts: Moved from QB to LB at Illinois State after thumb injury as freshman.

Overview: Demanding, intense perfectionist turned down Nebraska head-coaching job in 2004 to stay with Cowboys.