The same injury caused the fifth-year senior to miss the 2002 campaign. He played with pain in the Trojans' first two games this season, but tests have revealed he needs an operation.
"Kevin will need surgery to fix his foot," said Coach Pete Carroll. "We will lose Kevin for the rest of the season. It's a big loss to lose a leader and big-time playmaker."
A decision to seek another year of eligibility from the NCAA already has been made for Arbet, who was a walk-on in 1999 and subsequently earned a scholarship.
His place in the secondary will be assumed by fellow senior Will Poole, who came to USC last year as a college transfer from Ventura College. He started as a freshman for Boston College in 2000, but left after he was suspended for the 2001 campaign.