Mario Williams became the Houston Texans' cornerstone as the No. 1 overall draft pick in 2006, to say nothing of his defensive role. But as Houston's Wade Phillips-led defense transitions to the 3-4 scheme, Williams has again become a building block. Williams will move from defensive end to outside linebacker with the scheme switch, the Houston Chronicle has reported. Read more: http://sports.espn.go.com/nfl/news/story?id=6492434
