None of last year's starting linebackers will be back. Most of the defensive line is gone. The emotional leader, Mark Sanchez, also will be absent.
But instead of worrying about how these things will impact USC on its schedule, the spring is about something else. It's about the process.
Someone will be the Trojans' new starting quarterback, and it will play out over the course of the spring. Some unfamiliar faces will step up and make pushes for extended playing time. Some veterans will be working towards one last chance.
On a simpler level, it marks the start of change, and for players, that's a good thing.
"It gets like this before every season, and this is our senior season," Damian Williams said. "We've been working out for so long, and you almost get to the point where your body is almost immune to the work. It's kind of like we need a change a pace.
"We're tired. You can see it."
Now, though, the new format, new drills and new environment will serve as rocket fuel for the players' energy.
By the time USC takes the field Thursday, the first day in full pads, things should be at a boiling point.
For some guys, spring ball doesn't really begin until someone gets smacked in the mouth. Thursday, that will almost certainly happen.
Winter workouts are really the base as USC marches towards next season. They serve a significant purpose - getting the players ready for a competition-filled spring.
With so many different starting positions up for grabs, expect to see players operating at a very high level. Each rep will count for the linebackers; each throw will matter for the quarterbacks.
And for the team's leaders, like Williams, it's a time to get everyone on the same page and focused on a common goal - a national title.
Work starts Saturday morning, and the Trojans couldn't be more excited to clock in.