By Jim Thomas
Of the Post-Dispatch

For three years, the Rams tried to replace London Fletcher with undersized linebackers in Jamie Duncan (2002) and Robert Thomas (2003-04). But this offseason, they decided that size matters.

At 6-3, 255 pounds, Chris Claiborne is the biggest middle linebacker to play for the Rams since the move to St. Louis in 1995.

"Claiborne's got that presence in the middle that we've been looking for since London was here," coach Mike Martz said.

Actually, the Rams looked Claiborne's way two years ago, bringing him in for a visit early in the 2003 free-agency period.

"We were close to doing something, but I think at the time, they just had something else (in mind)," Claiborne said.

He signed instead with Minnesota, where he spent the 2003 and '04 seasons. But in March, the Rams finally pulled the trigger on a Claiborne deal - and pulled it quickly. On the second day of free agency, he was signed to a three-year, $10.5 million contract, including a $3.6 million signing bonus.

His mission in St. Louis is simple: Stop the run.

"We're counting on him," Martz said.

Counting on him to shore up the defense that ranked 29th in the NFL in yards allowed last season. Claiborne says he doesn't mind the pressure that comes with being the centerpiece of a revamped front seven.

"That's fine," Claiborne said. "I mean, that's just like going back to college. As a middle linebacker, you take that pride in the run game."

Back in college, Claiborne was one of the most highly touted middle linebackers in the game at Southern California. But a funny thing happened after Detroit selected him as the ninth overall pick in the 1999 draft: The Lions moved him to outside linebacker.

"I don't know why they brought me in to play outside," Claiborne said. "But a big body running on the outside in that division, it's very much power football there. That's what they wanted."

Except for the 2002 season and much of the 2001 campaign, Claiborne has played outside linebacker in his six NFL seasons with the Lions and the Vikings. Why?

"I can't speak for them," Rams linebacker coach Joe Vitt said. "I can speak for us. I think he's a prototype middle linebacker. He does have good range for a 255-pound man. He has good cover skills, and he's a heavy hitter."

He's not a bad blitzer, either, as evidenced by his 14 1/2 career sacks. But it's not just Claiborne's skills, it's his style of play and attitude that should provide a lift to the St. Louis defense.

"Chris, he's a physical guy," defensive lineman Tyoka Jackson said. "And his presence in the middle is going to help our run defense. He's all about blood, sweat and tears. You can tell. And we needed that to help our identity on defense."

During 2002, his one full season at middle linebacker, Claiborne established career highs in sacks (4 1/2), interceptions (three) and pass breakups (eight). His tackling total (145 stops) was the second-highest figure of his career.

Perhaps with that kind of production in mind, Claiborne set out in the offseason to find a place middle linebacker. Hello, St. Louis.

"I'm so happy," he said. "It's been a long time coming. It's very, very exciting, and I'm looking forward to the opportunity. ... I definitely bring a physical style. I take pride in stopping the run and blitzing."

Even though Claiborne wasn't on the field for many of those yards, his pride might have been stung by the 215 rushing yards allowed Sunday in San Diego.

"It was one gap here, one gap there," Claiborne said. "Those are things that can be corrected. If we just got blown off the ball, then I would be a little frustrated. Or a little concerned."

Even so, Claiborne said, "you can't allow the long runs." The Rams allowed two 55-yard runs by the Chargers, one that went for a touchdown and another that set up a touchdown.

"If they break the line of scrimmage, we've got to get the tackle," Claiborne said. "And we play another play, and we go from there."

On Monday, Claiborne returns to his original NFL home, Detroit, where the Rams play their third exhibition game. Not many of his former teammates remain on the Detroit roster. And after playing Detroit twice a year as a Viking, the matchup no longer is very meaningful.

How would he characterize his time there?

"It was all right," Claiborne said.

Nothing outstanding?

"No, nothing outstanding," he said. "It was all right."