Susac has been diagnosed with a left knee patella fracture, Justice delos Santos of The San Jose Mercury News reports.
Susac suffered the injury when he fouled a ball off his knee during Sunday's game versus the Tigers. The initial prognosis was a contusion, but an MRI revealed a fracture. Susac will meet with doctors Tuesday to determine the next course of action, but it's likely the injury ends his season. With Jesus Rodriguez (elbow) also sidelined, Drew Cavanaugh is the only healthy catcher on the Giants' 40-man roster.