"I think it's still a learning process," Rivera said. "Sometimes in the second year, people talk about the sophomore slump, and that's always a potential. Guys show a little confidence, and maybe they don't work as hard, but hopefully we've avoided that with a guy like Tommie. I think Tommie has done some terrific things during (the off-season). You also look for a guy like Tank Johnson to take the next step."
Last season, Johnson started out so impressively that some observers predicted he might outplay Harris.
But Johnson flamed out during the course of the season, and after getting a start in the third game of the year, he was strictly a backup after that. Harris, meanwhile, started all 16 games and often attracted double-team blocks to neutralize his disruptiveness.
Johnson still has the talent to wind up starting alongside Harris for years to come, and new defensive line coach Don Johnson is looking forward to Tank realizing that potential this season.
"Just based on his ability, his quickness and his athleticism (he should be much better)," Johnson said. "I would like to see him put the complete package together and get on the field with it."
Linebacker Lance Briggs did that last season in his second NFL season. Briggs led the team with 168 tackles and was second with 10 tackles for negative yardage.
"You look to see a Lance Briggs continue to develop," Rivera said. "Here's a guy that showed last year that he should be a force to be reckoned with in this defensive system."
Brian Urlacher was well on his way to another Pro Bowl season in 2004, but a calf injury and two separate hamstring injuries limited him to nine games. Entering his sixth season, Urlacher is still just 27 and should benefit from his second season in Rivera's system and from what is expected to be a better defensive line than last year's youthful and banged-up front.
"Having a year in this system, he'll be better," Rivera said of Urlacher. "(Head coach) Lovie (Smith) said last year -- and I agree with what coach said - 'There's never been a middle linebacker with his ability in this system,' and in this system, it could be tremendous what he does."