With Isaac Sopoaga anchoring the middle of the 49ers' defensive line the past few seasons, Ian Williams has played a bit role.In two seasons since signing as an undrafted free agent out of Notre Dame, the 6-foot-1, 305-pounder has been used as an extra defensive lineman in running situations and as a backup nose tackle when Sopoaga needed a play off. He played in three games last season and one in 2011, and has a total of just three tackles.But this season, it's possible Williams could be playing a much bigger role. With the departure of Sopoaga in free agency, Williams has been impressive in training camp so far at nose tackle, getting reps with the first-team unit.Though it was assumed that veteran Glenn Dorsey – acquired this offseason from the Chiefs -- would be the front-runner going into this sumer training camp, Williams is making a statement with his play.Matt Barrows, who covers the 49ers for the Sacramento Bee, wrote that Williams has been anchored on the defensive line between ends Justin Smith and Ray McDonald since camp began at Santa Clara."On the first play of team drills, he got underneath guard Alex Boone and flushed (quarterback Colin) Kaepernick from the...