San Francisco 49ers linebacker Aldon Smith speaks during a news conference at NFL football headquarters in Santa Clara, Calif., Friday, July 27, 2012. In his first public comments since he was stabbed... more 

San Francisco 49ers linebacker Aldon Smith speaks during a news conference at NFL football headquarters in Santa Clara, Calif., Friday, July 27, 2012. In his first public comments since he was stabbed at his home last month, Smith said Friday that "letting everybody down was probably the saddest part." He also was charged in late January with driving under the influence in Miami Beach. (AP Photo/Paul Sakuma) less