According to this tweet from ProFootballTalk, the Oakland Raiders will be meeting with TE Jermaine Gresham and DT Dan Williams.
Raiders to meet with TE Jermaine Gresham, DT Dan Williams http://wp.me/p14QSB-9J5n
Williams, out of the University of Tennessee, is a former first-round selection by Arizona in the 2010 Draft. Over the last five seasons, Williams has been in the Arizona defensive line rotation primarily as a block-eating run stuffer. He only has two sacks in his career and isn't really considered a pass rusher. He is a mountain of a man at 6'2" and 327 pounds.
If the Raiders cannot land Terrence Knighton (who some sources believe the Raiders are no longer actively pursuing) then Williams makes sense as a force in the middle of the line. The Raiders will likely look to add more pass rushers, but Williams is a good fit in the middle for a start.