On the same day Seattle Seahawks wide receiver Percy Harvin underwent surgery to repair an injured hip, the San Francisco 49ers have apparently lost a defensive back for the season.
According to Adam Schefter of ESPN.com, 49ers cornerback Chris Culliver suffered a torn ACL in practice on Thursday and will miss the entire season.
49ers CB Chris Culliver did tear his left ACL. No date for surgery set yet. He will miss this season.
— Adam Schefter (@AdamSchefter) August 2, 2013 
Source: Curtis Crabtree, NBC Sports Pro Football Talk