Walt Harris injured his ACL in Tuesday's practice when he became tangled with receiver Dominique Zeigler along the sideline. Harris stayed down for several minutes after the play and had to be helped by a trainer to a nearby cart. Harris will have surgery on the knee either next week or the week after. The 49ers have not given a prognosis, but we all know that when the ACL is involved there's a very good likelihood that it will be a season-ending injury.