Defense has always been a staple for the Alabama football team. That can make it tough to believe how words like  “liability” and “weakness” have been used to describe a unit that has ranked third and second in total defense the last two seasons, respectively.

It’s a matter of inexperience. After losing nine starters from last year, including leaders Rolando McClain, Terrence Cody and Javier Arenas, it’s natural to doubt. And although their replacements have talent, they don’t have the playing time to validate it.

Head coach Nick Saban will be the first to tell you freshmen don’t have talent until they prove it on the field. And although he said the Tide is comfortable heading into the season with its current defensive roster, he remains concerned about the continuity within the unit, particularly in the secondary, because of injuries suffered in fall camp that kept players out of practice.

“I feel comfortable with the players we have,” Saban said. “The thing that has been most difficult during this camp is that when you have a new group of guys that haven’t played, you’d like to get continuity, but we have had guys out and we haven’t been able to do that.”

Even a few of the defense players who have already made names for themselves have question marks over their heads heading into 2010.

Sophomore linebacker Dont’a Hightower had a stellar freshman season, but he is coming off of reconstructive knee surgery and will have to prove his durability. Defensive lineman Marcell Dareus stepped in last year and played great in the national championship game, but his eligibility is in question while the NCAA investigates a party thrown by an agent that Dareus may have attended.

Junior defensive back Mark Barron, the only returning defensive player to start every game last season, will be one of the players asked to play a huge role for the Tide’s secondary this year. He will make more calls and adjustments for the entire defense. Last year, Barron led the Southeastern Conference in interceptions.

“We had a talk at dinner [on August 25] – me and [William] Vlachos, actually – about how good Mark [Barron] really is,” senior quarterback Greg McElroy said. “I think a lot of people think of him as a playmaker, a guy that’s just so great in coverage, but one thing he does is just read eyes. He’s got such great instincts.

“I can think of a play [August 25] where I threw the ball with good timing to [Darius] Hanks on an option route, and Mark [Barron] was not necessarily in the greatest position, but he made a great recovery, and he picked the ball off. I think it’s a credit to those guys being opportunistic.”

Despite the new faces, the Tide remains optimistic about its chances to have a great year and uphold the identity of a typical Alabama defense. Just ask some of the offensive players whether they’ve enjoyed facing that defense every day during fall camp.

“I’m tired of going against them every day,” junior tight end Brad Smelley said. “The defense has improved a lot. Those guys, they’ve been working hard, and you notice it going against them every day. The defensive backfield is coming together. Our linebackers have improved – those are some big guys, good guys that can play, play the run, play the pass. They can do it all. And d-line, there’s some hosses in there for sure.”

Said McElroy: “I think you’ve got to give credit to the defense because when the plays have been there to be made, they’ve made the plays.”

The young players have been stepping in and trying to prove that they are ready to be on the big stage. A freshman class that’s eager to learn has impressed some of the team’s veterans during fall camp.

“It shows out there on the field,” Hightower said. “Guys, whenever they mess up, they’re always asking questions. They go straight to the coach on the sideline. You don’t have to tell the young guys to break on the ball or try harder.

“It surprised me a lot. Whenever you have young guys come in, you’re always going to have older guys be like, ‘Let’s go watch film.’ But with these guys, they want to play. They’re asking the older guys to come in and watch film. There’s something that impresses me a lot about the freshmen.”

Saturday’s game against San Jose State will hardly answer whether Alabama can sustain the same kind of dominance on defense as the past couple seasons, as San Jose State ranked 115th out of 120 FBS teams in total defense last year. The Tide secondary doesn’t have long before a true test comes, however. Alabama’s third and fourth opponents of the season (Duke and Arkansas) both have offenses that ranked in the top 10 in the nation through the air last season.

But Alabama’s defensive goals stretch beyond the top 10.

“Our goals are just to be the best,” linebacker Chris Jordan said. “Everybody’s working hard to be the best. I feel really good about the defense.”