If you ever get the chance to shake senior center Khaled Holmes’ hand, don’t be surprised if your hands completely disappear in his grip. Holmes’ hands are massive for a reason.

It’s a snap · Holmes leads an offensive line that returns four starters and only yielded eight sacks in 2011, the fewest in the nation. – Carlo Acenas | Daily Trojan

Though the offensive firepower of USC is epitomized by the precise arm of senior quarterback Matt Barkley and the agile legs of sophomore wide receiver Marqise Lee and junior wide receiver Robert Woods, the play always starts in the hands of the center.

Ever since he switched over to center from right guard last season, Holmes has grasped this crucial and often unappreciated responsibility and has never let go.

In Holmes’ first year at the position, Holmes and left tackle Matt Kalil, who now plays for the Minnesota Vikings, bolstered an offensive line that gave up just eight sacks, the fewest in the country.

The line also helped the run game average 4.98 yards on the ground, good for third in the Pac-12.

Now, Holmes and the line will attempt to match those feats without Kalil, who was drafted by the Vikings with the fourth pick.

“I was nothing but happy for [Kalil],” Holmes said. “He was the best lineman in the draft, and he’s going to be a great player in the NFL.”

The praise comes from the heart, but it also represents the void that Kalil will leave behind.

“He left some big shoes to fill,” Holmes said.

Barkley, who has played quarterback with Holmes protecting him at the line since their days together at Mater Dei High School in Santa Ana, has no doubts that his longtime friend will embrace the challenge.

“[Holmes] is the guy. He’s the guy to center that line and anchor it,” Barkley said. “He’s really established himself, I think, as one of the premier centers, if not linemen, in the country.”

Along with Holmes, three other starters on the offensive line will return in junior right tackle Kevin Graf, junior guard John Martinez and sophomore guard Marcus Martin, but gone are the days of Kalil reliably protecting Barkley’s blindside.

Now more than ever, Holmes will step up as the leader of the line as the Trojans gear up for a national championship run. Having a year of center experience to build on will definitely help.

“It’s like anything -— the more you do it, the more comfortable you are, the better you get at it,” Holmes said. “I was a little apprehensive with some things last year, but, day by day, it got more and more comfortable.”

Holmes started his USC career as a backup right guard during his redshirt freshman season in 2009.

As a sophomore, Holmes started every game at right guard and earned All-Pac-10 honorable mention honors.

After center Kristofer O’Dowd graduated, Holmes took his place and was named to the 2011 All-Pac-12 second team.

He is now a leading candidate for the Rimington Award, given to the best center in the nation, and he certainly has the credentials to lead the Trojan linemen into the trenches and be what he calls “a coach on the field.”

As the center, Holmes must have the body to withstand and neutralize a defense’s nose tackle. His 6-foot-4, 305-pound build takes care of that.

He must also have the brains to recognize defensive schemes and adjust blocking assignments before the play.

His pursuit of a master’s degree in communication management might speak to that.

And lastly, he must have the chemistry with the quarterback for pinpoint timing and successful snaps. His friendship with Barkley since the sixth grade exemplifies that.

It’s no coincidence that Barkley and Holmes are now the two offensive captains.

“I’ve known him forever, so we actually have a really good relationship,” Holmes said. “I think that extra trust and understanding has been nothing but helpful.”

Because nearly every play USC runs this season will begin with Barkley and Holmes, it is vital that the two are in sync.

It seems that it would be difficult for the two of them not to be.

“He’s played every position on the line for me — left tackle in high school, and guard and now center,” Barkley said. “I’d say we’re best friends on the team.”

Their relationship continues to grow every day with every snap on the field and every minute together off the field.

“We live right next to each other. We spend a ton of time together, and I think that just helps with knowing each other, making jokes and letting some things slide,” Barkley said. “We don’t get angry at each other. We understand each other on the field.”

Once the season is over, Holmes will find himself alongside Barkley yet again — this time at the 2013 NFL draft — but, until then, his hands are holding on tight for what could be a memorable last season at USC.

“I’ll approach this year like every other,” Holmes said. “But I’ll look up every minute and realize that everything I do is going to be last time I do it here. It’s pretty crazy how fast it’s gone by.”