Wideman, it seemed to me, lost his confidence at some point late in the season and never got it back. He struggled mightily in the playoffs, but he wasn't helped by playing with a similarly struggling Jeff Schultz.
I also have to wonder if his serious leg injury from the previous season hampered him at all. He didn't seem to move very smoothly, at times, after playing some big minutes while Green was out.
I don't know for sure, but I doubt Wideman will be an issue next season. Seems he'll get more money and term from someone else, given that he's UFA.
I must disagree with your comment about Semin. He was praised -- and deservedly so -- for his performance early against Boston. But he had ONE point (and a bunch of forehead slapping turnovers) in the Rangers' series. That's not good enough for a player of his skill level.