The ravens have kept lewis because he's been the best mlb or right up there for, like, more than a decade. Vilma has NEVER been anything even remotely close, please don't start comparing the two.
It's good to have a leader and so on, but a leader who can't play is USELESS. Did you see the giants saying "please come back even if you're not good enough and oft injured" to antonio pierce? I didn't. And he was 10 times the leader vilma has been to us, please.