As much of the rest of the defense did throughout most of 2009, the linebacker corps for N.C. State struggled a year ago.  With senior linebacker Nate Irving unavailable while recuperating from a severe car accident before the season and players like then-redshirt freshman linebacker Terrell Manning seeing playing time early in their careers, the Wolfpack’s situation at linebacker was anything but stable.   This year, it is a much different story on the defensive side of the ball for the 4-0 Pack. With many of the same players in the fold and defensive coordinator Mike Archer still calling the shots from the sidelines, the faces on the Wolfpack defense are largely the same – with one notable addition. New to the defense is linebackers coach Jon Tenuta, who coach Tom O’Brien said has teamed up with an improved linebacking group in leading the turnaround.   “Jon is a good coach, I don’t think anyone is going to dispute that, or his ability to coach the linebackers,” O’Brien said.  ”I feel like he came into a good situation as well.  Because Nate [Irving] returned and he is a great player, and knock on wood, he stays healthy.  And redshirt junior Audie [Cole] and Terrell [Manning]  have matured a lot and grown up over the last year.”   In Tenuta’s first four games coaching the linebackers, the defense’s statistics are drastically better than they were a year ago. So far, State has given up 18.8 points per game just one season after allowing eight of 10 FBS opponents to score 30 or more. Through four games, the Pack has already tallied 14 sacks and forced nine turnovers, putting it on pace to nearly double its 2009 totals in those categories.    Another big statistical difference under Tenuta has come on third down. In 2009, State allowed opponents to convert 44 percent of third down attempts. This year, Wolfpack opponents are converting on only 25 percent of third downs.     “We play faster when we are more aggressive,” O’Brien said. “I think [Tenuta] has helped us.  The third down packages that we have put together through spring practices and during preseason have helped us.  We might not always get a tackle for a loss or a sack, but if we get a hurry, the quarterback starts thinking, ‘Which direction are they coming from next?'”   No position group has been more responsible for the big plays than the Tenuta-led trio of linebackers, who have collectively accounted for 12.5 of the team’s 29 tackles for loss. Cole has one of the team’s three interceptions, Manning has recovered two fumbles and forced one, and Irving has also forced a fumble. All three have also recorded two sacks apiece. This type of play has led to both Cole and Irving winning ACC defensive player of the week awards.   2010 is by no means Tenuta’s first stop in the ACC.  He graduated from the University of Virginia as a star defensive back for the Cavaliers before he became a coach.  His run in the ACC did not stop there, as he was named the defensive coordinator for State’s rival, UNC-Chapel Hill, in 2001. 2001 was one of the Tar Heels best seasons defensively, as Carolina finished the year with the conference’s top-rated defense.  Tenuta then moved on after one stellar season with the Heels to Georgia Tech.  During his tenure from 2002 to 2007 with the Yellow Jackets, Tenuta helped 18 players earn All-ACC recognition and coached 18 players who were drafted or signed NFL contracts.   Saturday the Pack will be relying on the defense to continue its success against dual-threat quarterbacks.  In the past three weeks, State’s defense has faced Central Florida’s Jeff Godfrey, Cincinnati’s Zach Collaros and Georgia Tech’s Joshua Nesbitt, three gunslingers who can run and pass the ball efficiently.  But O’Brien said he knows his team will have its hands full against Tyrod Taylor and Virginia Tech.   “For the past three weeks, we have faced quarterbacks like Tyrod Taylor, but quite frankly, he is better,” O’Brien said.  ”At least we’ve coached and understand the type of things that we will have to do against Taylor.”   Tenuta will look to have his linebackers ready Saturday at 3:30 p.m. when the defense will look to help the Pack continue its winning ways in front of a sell-out crowd at Carter-Finley Stadium.