This Richards injury is starting to sound more and more like the Crosby saga. FML
Oh honey, it's so far from the Crosby saga it's funny. Crosby suffered two concussions in the course of four days.
Generally, concussions are 7-10 days out but can be slightly longer if the symptoms take longer to resolve. Without a history of concussion or something stupid like letting the player return before a week without symptoms, being out an extended period of time isn't a huge concern.
Rule of thumb is a week from the end of symptoms before you're allowed to start working out. They're holding hom so it doesn't turn into the Crosby saga.