Cornerback Adoree' Jackson, receiver JuJu Smith and tight end Bryce Dixon -- all freshmen -- have played substantial roles for USC this season.
Freshman safety John Plattenburg could be next.
With Gerald Bowman nursing a thigh injury suffered against Arizona State, Plattenburg could play extensively Saturday night at Arizona if the senior does not play or is limited.
Bowman did not practice Tuesday or Wednesday. Sarkisian said he practiced Thursday during a workout that was closed to the media.
"I imagine he goes," USC Coach Steve Sarkisian said of Bowman. "To what extent, I don't know. Those things are tricky because it's one hit right back on that thigh and it feels the way it feels."
Plattenburg has played in three games but does not have a tackle.
"He's going to have to execute the stuff that we're asking him to execute," Sarkisian said, adding that for freshmen, "it's not just JuJu and Adoree' anymore.
"It's a lot of guys that are getting opportunities and we expect them to perform."