Our series on 2012 contributors gone from NFC West rosters concludes with a look at the San Francisco 49ers.2012 49ers Gone from RosterPlayers responsible for logging 85 percent of the 49ers' offensive and defensive snaps last season remain on the 90-man roster at present. That is a high figure, but it's also telling only part of the story.Receivers Michael Crabtree and Mario Manningham remain on the roster, but neither is healthy enough to contribute.