Daryll Clark drops back behind the first-team offensive line during a spring practice scrimmage. But instead of being cloaked in a blanket of secure protection, second-string defensive tackle Tom McEowen penetrates the line and applies pressure, forcing Clark to rush his throw.

For much of Saturday's scrimmage, Clark and fellow quarterback Pat Devlin were pressed for time in the pocket, regardless of whether they were facing the first- or second-string defense, something defensive end Josh Gaines said is a credit to the depth of talent along the defensive line.

"We've got guys that could start anywhere," Gaines said. "Anybody could step up and start anytime. That's why I'm looking forward to the season, we keep rotating, no matter who starts the game."

That rotation has become a staple of defensive line coach Larry Johnson Sr.'s coaching style.

Only four linemen start for Penn State, but Johnson runs new players onto the field throughout the course of a game. Last season, seven defensive linemen played in at least 12 games -- Jared Odrick only competed in eight because of an ankle injury.

But that rotation has been thinner during spring practice.

Defensive tackles Chris Baker and Phil Taylor have been suspended from the team because of off-the-field violations. Odrick is not fully recovered from the injury, and defensive end Devon Still has only been cleared to run as he rehabs a torn anterior cruciate ligament (ACL).

While Baker and Taylor have not been allowed to practice with the team this spring, Gaines said the two have continued to work out on their own in hopes of a possible return in the fall. Odrick, meanwhile, has been allowed to participate in some drills but is still limited in what he can do.

With these four linemen gone from spring practice, inexperienced players, such as tackles Ollie Ogbu and Abe Koroma have been thrust onto the starting line. It's also given reserves, like McEowen, an opportunity to get more repetitions in practice -- and an opportunity to move up the depth chart.

"I think we're in good shape," Joe Paterno said. "We don't have the experience you'd like. Baker and Taylor have played a lot of games and have been good. But I'm hopeful everything will settle down, and maybe we'll have them in the fall, but I'm not sure."

Until then, it's up the reserves to embrace their increased roles and uphold the tradition of Penn State defense, which has not ranked lower than 15th in total defense since 2003.

But just because he's lining up next to sophomores and freshmen, Gaines said the competition level during practice has remained high. He said Johnson has done a good job of identifying quality line recruits, such as Ogbu and Koroma, who can compete for starting spots early in their careers.

And with so much uncertainty, especially at tackle, Gaines said his defensive line coach has left the starting spots open for competition. This has led to intense practices, according to Gaines, which he said should translate into another solid season for the defensive line -- with or without the suspended players.

"You've got to come to practice ready to play," Gaines said. "If you don't, you're going to get passed. That's what Coach J says, whoever's most ready is going to start."