USC loses starting center Kilian O’Connor for the season after knee injury in practice, Lincoln Riley says

USC is headed into its season opener with a major early setback. Lincoln Riley announced that starting center Kilian O’Connor suffered a season-ending knee injury during practice, removing an established anchor from the Trojans’ offensive front just weeks before their Aug. 29 opener against San Jose State.

Center is more than a spot on the depth chart in college football. The position touches every snap, sets protections and calls, and often serves as the line’s communication hub. With O’Connor sidelined for the season, USC will need to reshuffle the middle of its offensive line and rebuild continuity quickly in August.

The report frames the injury as occurring in practice, with Riley delivering the update as the team moves through preseason preparations. That timeline matters because preseason repetitions are typically the narrow window coaches use to establish who can handle snap responsibilities and the mental demands of the position under full-speed work.

USC enters the year with expectations that include fine-tuning execution along the offensive line. The Trojans’ ability to maintain rhythm in the running game and protection packages is likely to be closely watched as new combinations take their first extended reps together.

While USC has to solve the immediate center question, the knock-on effects of losing a starting interior lineman usually show up beyond the first snap. Depth choices at guard and tackle can shift, and teams often adjust their protection calls depending on who is available to play next to the center.

USC’s coaching staff now faces a narrow practical challenge. In the remaining weeks before the season starts, the Trojans must identify who is prepared to start at center, determine how the rest of the line should be arranged around that choice, and ensure the unit can carry those decisions into a Week 1 matchup against San Jose State.

What to watch next is how USC structures its offensive line rotation in fall camp and which lineman emerges as the center replacement in the lead-up to kickoff. The Trojans’ early-season offensive efficiency, especially in pass protection, will be a revealing early indicator of how quickly the lineup stabilizes after the loss of O’Connor.