The San Francisco 49ers have confirmed that Chris Culliver sustained an anterior cruciate ligament tear during yesterday's practice.
The cornerback picked up the injury during a punt return drill with rookie Marcus Cooper.
The San Francisco Chronicle reported that the 24-year-old was in tears as he left the practice field being comforted by 49ers general manager Trent Baalke.
It is expected that Culliver will need surgery to repair the injury, which would keep him off the field this season.