But to diehard fans, who know the ins and outs of this football team, it's likely that "7" is worn to celebrate All-American safety T.J. McDonald.
But on Friday night, there will be two new safeties taking the field, different from the ones who've started all season. Because of an injury to Jawanza Starling and a half-game suspension for McDonald, Drew McAllister and Marshall Jones will hear their names called when USC takes the field in Boulder, Colo.
And while neither McAllister nor Jones has played significant minutes this season, both say they're ready to shine under the Friday Night Lights.
"I prepared all week like I'm going to start. I'll just take advantage of my opportunity," McAllister said.
"I don't feel any pressure I'm just looking at it as an opportunity to showcase my talents," Jones said.
McAllister will start in place of McDonald, Jones of Starling. Although the two act, talk and play differently, these roommates' paths to this point have been relatively similar.
Both upperclassmen, McAllister and Jones experienced the Carroll to Kiffin transition together. And the new coaching staff wasn't readily accepting of either player.
Jones was sidelined his junior year because of neck surgery, and briefly considered transferring because he felt he had to prove himself all over again.
McAllister's junior year was spent getting back-to-back hip surgeries. He felt few from the Kiffin era had seen this ball hawk play.
"It was hard to come back from that, I took about a year and a half off and on. There were times I really wanted to be out there and just couldn't," McAllister said.
"They knew the freshmen, but they didn't even know who I was at first. That set me back. I was humbled a lot," Jones said this summer.
And on Friday, when these roommates take the field together, they will both have the same person on their mind: their moms.
McAllister steps onto the field thinking of Tracy, who almost singlehandedly raised the Danville (Calif.) Monte Vista kid since a young age. Likewise, Jones' motivation comes from his mom and sister, whose names are tatooed on each of the Westlake Village (Calif.) Oaks Christian product's wrists.
Both have also had career starts before. Jones started four games in 2010, again for an injured Starling. In 2009, McAllister started USC's game in Washington.
But the two differentiate in terms of their style of play. Jones is the more physical of the two, better at clouding a player rather than working in open space. McAllister, on the other hand, has an uncanny magnetism to the ball, attributing his vision to being a quarterback in high school.
While it's only one game, against an arguably lesser Colorado opponent, these two players who do so much together, will split the field together Friday, relying on brotherly instinct and trust to guide them in their first big game in 2011.
If they can be successful, Jones and McAllister could very easily see more of the field in the future. Maybe fans will soon buy a No. 27 or No. 19 jersey then, too.