"I'm not really sure of the science on it, but we'll just sit tight," coach John Harbaugh said Monday. "The thing we've learned to do with concussions is to assume that they're out until they're back. You just can't count on those guys. We had [offensive tackles] Oniel Cousins and Tony Moll [suffer concussions] in training camp, [and] it seemed like forever. And other guys come back the next day. [Rookie kick returner/wide receiver] David Reed's another guy who is in that boat right now. We've got to see how he does, too. So we'll keep our fingers crossed for both of those days."Harbaugh did sound more optimistic about inside linebacker Tavares Gooden, who re-aggravated the left shoulder that he dislocated in the team's 15-10 loss to the Cincinnati Bengals on Sept. 19.