This is Part 7 of the 10-part position analysis leading up to the start of the Bears’ 2010 training camp in Bourbonnais.

The Bears added a key player to their defense this off-season and they didn’t have to look outside the organization to do it. And no, I’m not referring to defensive end Julius Peppers, who came over from the Panthers. I’m talking about the aging, but still critically important middle linebacker Brian Urlacher.

Urlacher played less than one half of football last season before dislocating his wrist in the season opener against the Packers and being placed on IR. The fact that it was just a season-ending injury and not one that ended his career is a major blessing.

Critics will claim that Urlacher is washed up and his best years are behind him. While I can agree with the latter part of that argument, the former is just not true. Urlacher still has immeasurable value and fans won’t have to wait very long to sense that. I’m guessing they’ll realize it by the first week of the season.

Lost in the anger and frustration that Bears fans have over the performance of last year’s defense — which included four losses of at least 20 points — is the fact that the defense played almost the entire season without one of its best players. Urlacher’s veteran leadership, his still impressive speed as well as his athleticism and unmatched talent in the Cover 2 defense were sorely missed last season. His ability to cover the deep middle will change the way opposing offenses operate.

With Urlacher back, responsibility to cover certain weaknesses will cease for Lance Briggs. Briggs is now in the prime of his career and with the additions of Peppers, Urlacher, and Chris Harris, Briggs should be well on his way to his sixth-straight Pro Bowl this season, assuming he stays healthy. It’s become a cliche, only because it’s been said so much, but Peppers’ addition to the team should help Briggs excel even more than he did last year. Assuming Peppers and the rest of the defensive line can increase pressure on opposing quarterbacks, that frees up Briggs to roam the second level and not have to blitz the quarterback as much.

Who starts at strongside linebacker next to Urlacher and Briggs remains a question mark. The logical choice is Pisa Tinoisamoa, whom the Bears signed to a one-year deal last year but who failed to play in more than two games due to a knee injury. The Bears decided to give him another chance by re-signing him this off-season, but he’ll have to compete with Nick Roach for the starting job. Roach played admirably last season while filling in for Urlacher and Tinoisamoa.

Despite trading Jamar Williams to Carolina for Harris, the Bears still boast great depth at the linebacker position. Hunter Hillenmeyer is solid although not spectacular. He’s capable of filling in in a pinch and knows how to play all three positions — although his lack of athleticism would prohibit him from playing the weakside. Tim Shaw returns after a great season on special teams. Bears fans love him for his passion and intensity and coaches don’t seem to argue that. The Bears also brought in Brian Iwuh from Jacksonville, who is also a solid special teams player. And Kevin Malast had a good preseason last year and will be back to compete for a roster spot this year.

Of all the moves the Bears made this off-season, signing Peppers was clearly the most intriguing. After all, you don’t pay a guy $90 million to have a marginal impact on your season. But it is my belief that Urlacher’s presence in the lineup will have almost as much impact on the performance of the defense as Peppers’ will. With an improved defensive line and pass rush, I’m excited to see the trio of Urlacher, Briggs, and either Tinoisamoa or Roach flying around and making plays.

Let’s just hope they all stay on the field for 16 games.