Ray is not replaceable, but Next Man Up. Suggs has an incredibly strong personality and I think there are enough guys on the defense that saw how Lewis worked that I am hopeful they can continue the tradition of excellence. I am secretly hoping that Upshaw develops into the leader for the next generation.
On the offense, this is now Flacco and Rice's team to lead. They may not be vocal, but the offense seems close knit. I think they could bring a trouble player in and keep him in line.
All that being said, I would not spend too much time going after Titus Young. I don't think he would be a good fit.